No idea what to buy. Help me with recommendations please.

[dhokes]

With a failing hard drive on my iMac, I’m looking at possible long term solutions and could do with some advice as to what’s best for my needs. Sorry for the many questions as I'm very new to this sort of stuff!

I’ll be getting a MacBook that I want to back up regularly (probably best to use Time Machine?). I’ve also got a few external hard drives containing videos that I want to collate so that they’re together and be able to stream on Plex. I don’t believe they need to be transcoded. I’ve got a large mp3 collection too and not sure whether to keep it on my laptop or the final solution. I want to be able to access the songs on my laptop and on my phone. I don’t particularly need any of it to be accessible outside my home network. I believe I could transfer the music I want to my phone. I’ve also got things that I want for medium term storage that I may want to access e.g. photos, tutorials, ebooks. Apart from the time machine backups (or included, if it’s easier), I want everything to be backed up in case a disk starts to fail.

Summary:

• Time machine backups
• Videos (Plex)
• Music + other medium term files
• The above two I wanted backed up too.

What would you suggest that’s easily available in the U.K.?

I’m confused about RAID. Would you suggest it? If a video or a file becomes corrupt, I don’t need immediate access as long as there’s a backup available that I could use. Or is it good practice to use RAID so backups are available if files get corrupted?

Would I generally be better off by buying the enclosure + hard drives separately?

I understand the cost vs speed/efficiency argument of HHDs vs SSDs. What’s the typical life cycle for each? I don’t want to have to keep replacing them.

Should I avoid certain branded hard drives and only consider certain ones? I've hard bad experiences with Seagate external hard drives before.

Finally, does the NAS have to be connected directly to the router or can it be elsewhere and connected by power line adapters?

Sorry, I'm sure I'll have future questions later on.

 

[dhokes]

Also, are there are particular retailers in the UK that you'd recommend to buy hard drives from i.e. that have decent packaging and customer support if they fail?

 

[mickevh]

NAS's store files and serve them out over a network via things called "shares.". Any files, it doesn't matter what they are.

If you want a NAS that does "extra" things over and above basic file storage such as backup, plex, (which isn't at all required to stream media but a lot of people like it,) and so on, then you need to seek a NAS that either includes such apps or can be tailored to install them.

Wiki's article on RAID isn't bad if you want a primer. But it's important to understand that RAID is not in any sense "backup." RAID won't save you from corrupted files; if you write corrupt file to a RAID set or inadvertently delete it or get crypto-locked etc. RAID will not save you. Your data is gone/corrupt.

What RAID does is avail continued access to your data in the event of a disc failure (they all die in the end) whilst you go about replacing the failed disc. Some RAID versions (called "levels"in RAID speak) don't even do that.

Backup means making a duplicate of your data "somewhere else" for safekeeping. How often to make a backup, how long to retain them, how many versions to retain are decisions informed by things like the value of the data, how often it changes, how difficult it will be to recreate it, how much storage (and therefore cost) it will entail to maintain the backup sets and so on. Backup is more of a "regime" than some particular piece of software or hardware. Once you'd assessed the value of the data, how often it changes, recovery expectations, etc. you can then go shopping for a solution that meets your needs and budget. There's no "one size fits all" solution for backup.

SSD's are faster (and quieter, cooler and IIRC use less power,) than mechanical HDD's, but you get much less storage for your money. Generally, we don't bother with SSD in mass storage devices like NAS for the SOHO use case as most contemporary mechanical HDD and more than fast enough for domestic needs. So we buy mechanical HDD's and get more storage for our money.

There's no particular brand of HDD that's universally good or bad (I briefly worked for one of them, though not in the storage team.) All the manufacturers have their hits and flops, just like car companies. There's a web site somewhere that's maintained by HDD obsessives that charts the current trends of which products are good and bad. I forget what it's called, but someone here will remember.

 

[dhokes]

NAS's store files and serve them out over a network via things called "shares.". Any files, it doesn't matter what they are.

If you want a NAS that does "extra" things over and above basic file storage such as backup, plex, (which isn't at all required to stream media but a lot of people like it,) and so on, then you need to seek a NAS that either includes such apps or can be tailored to install them.

Wiki's article on RAID isn't bad if you want a primer. But it's important to understand that RAID is not in any sense "backup." RAID won't save you from corrupted files; if you write corrupt file to a RAID set or inadvertently delete it or get crypto-locked etc. RAID will not save you. Your data is gone/corrupt.

What RAID does is avail continued access to your data in the event of a disc failure (they all die in the end) whilst you go about replacing the failed disc. Some versions (called "levels"in RAID speak) of RAID don't even do that.

Backup means making a duplicate of your data "somewhere else" for safekeeping. How often to make a backup, how long to retain them, how many versions to retain are decisions informed by things like the value of the data, how often it changes, how difficult it will be to recreate it, how much storage (and therefore cost) it will entail to maintain the backup sets and so on. Backup is more of a "regime" than some particular piece of software or hardware. Once you'd assessed the value of the data, how often it changes, recovery expectations, etc. you can then go shopping for a solution that meets your needs and budget. There's no "one size fits all" solution for backup.

SSD's are faster (and quieter, cooler and IIRC use less power,) than mechanical HDD's, but you get much less storage for your money. Generally, we don't bother with SSD in mass storage devices like NAS for the SOHO use case as most contemporary mechanical HDD and more than fast enough for domestic needs. So we buy mechanical HDD's and get more storage for our money.

There's no particular brand of HDD that's universally good or bad. All the manufacturers have their hits and flops, just like car companies. There's a web site somewhere that's maintained by HDD obsessives that charts the current trends of which products are good and bad. I forget what it's called, but someone here will remember.

If I get something like the Synology DS920+, and I want to backup the contents of it i.e. 32TBs worth what are my options? I guess I could connect an external hard drive to it and do manual backups as/when I want? Is there an option to backup to the cloud and if so, given the sizes, I'm guessing there wouldn't be any free options? What sort of cost should I expect to pay for something like that? Any other options?

 

[mickevh]

There are certainly services that avail backup to what in known these days as "cloud storage" (back in the day, we used to call them "over the wire" backup services,) but I doubt you'd find a free one for 32TB of storage.

In the UK, my ISP, for example, offers one called a "digital vault" and there's things like OneDrive, SkyDrive, DropBox and so one. You'd need to have take a look at the T&C's and see how much you get for free and maybe whether there's options to avail more on payment of a fee. I'd also check the T&C's cartefully - I once read the ones for DropBox and the data ownership they asserted gave the willies!

You'd also want to check what, if any, automation is provided and granularity (how many backup sets they keep, how long for, etc.) as some may avail you the storage but it's up to you to actually make the backups.

Automating your backup regime as much as possible is, I would suggest, desirable. Making backups is a thankless boring task, and no matter how good one's intentions, it very quickly gets forgotten. If it's automated, it'll happen more often - though one really ought to check the logs regularly and make sure they backups are actually happening.

If we were really fastidious, we would check that we can actually restore from our backups from time to time (another thankless task.) It's amazing, even in big business, how rarely anyone checks that their backups actually "work" and they have expertise to restore them.

 

[dhokes]

Automating your backup regime as much as possible is, I would suggest, desirable. Making backups is a thankless boring task, and no matter how good one's intentions, it very quickly gets forgotten. If it's automated, it'll happen more often - though one really ought to check the logs regularly and make sure they backups are actually happening.

Yep, that would be my aim however I'd like to keep costs down. Just had a look at Synology's C2 storage pricing and don't think I could justify that cost tbh.

 

[next010]

A DS418 would be sufficient and lower cost than the DS920+.

The Synology can do

• time machine backup target for macs
• run plex
• automated backups to USB storage or cloud storage.

The DS418 cannot do any hardware video transcoding so your reliant on the Plex client being able to play the media. It can do some limited software transcoding via the CPU but only SD video and music.

For Apple devices I recommend using InFuse or MrMC, these have Plex support and play everything locally on the device instead of relying on server side conversion (transcoding) like the regular Plex clients do.

The DS920+ can do hardware video transcoding but Plex lock this feature behind Plex pass subscription.

 

[jamieu]

With a failing hard drive on my iMac, I’m looking at possible long term solutions and could do with some advice as to what’s best for my needs. Sorry for the many questions as I'm very new to this sort of stuff!

I’ll be getting a MacBook that I want to back up regularly (probably best to use Time Machine?). I’ve also got a few external hard drives containing videos that I want to collate so that they’re together and be able to stream on Plex. I don’t believe they need to be transcoded. I’ve got a large mp3 collection too and not sure whether to keep it on my laptop or the final solution. I want to be able to access the songs on my laptop and on my phone. I don’t particularly need any of it to be accessible outside my home network. I believe I could transfer the music I want to my phone. I’ve also got things that I want for medium term storage that I may want to access e.g. photos, tutorials, ebooks. Apart from the time machine backups (or included, if it’s easier), I want everything to be backed up in case a disk starts to fail.

Summary:

• Time machine backups
• Videos (Plex)
• Music + other medium term files
• The above two I wanted backed up too.

What would you suggest that’s easily available in the U.K.?

Synology or QNAP

A 4 bay will give you some room to add extra drives in future and you could just start with two high capacity drives in a RAID or SHR configuration. Something like a DS420j if you're on a budget or a DS420+ if you want an x64 (Celeron) processor and a bit more grunt to handle to occasional transcode.

Plex Transcoding, Docker (some package now come as Docker containers, Logitech Media Server/LMS is one that springs to mind) and some software that only supports an x64 architecture (Roon is one example) are reasons you may want to move up to the higher models. But if it's just for storage and Time Machine backups the entry level models will be fine for home use.

The DS920+ has slight higher maximum memory capacity that the DS420+ which may be useful if you plan to run lots of applications on it. In the end it problay comes does to the cost difference between the models and a long hard think re. what you are really going to use it for. You can always run application like Plex or Roon on their own small form PC's like an Intel NUC. Which may seem counter-intuitive, but the cost difference between the lowest and highest specs NAS's is probably more than the cost of a used NUC and even the highest spec NAS's still tend to use pretty lowly processors by modern desktop PC standards. So may be worth thinking of the NAS as simply a storage device, rather than a general purpose server and then sitting a i3 NUC on top of it (as a headless server) to run the most demanding applications should that need arise.

Synology for sure supports Plex and TimeMachine, fairly sure QNAP does too.

Synology can run Plex, LMS (in Docker), Roon, a DLNA server or it's own Audio Station package so lots of options for music library management. Synology can also host an iTune library.

You can also use something like Kodi (the Vero 4k+ is a good option if you want a dedicated Kodi device) to playback your files direct from a standard SMB/Network share, so no media sever (like Plex) needed on the NAS at all. Likewise you can simply mount a folder containing music or films onto your Mac and play them back using whatever software you like.

I’m confused about RAID. Would you suggest it?

If using a Synology, then their Synology SHR (their version of RAID 5) will cover your needs and almost certainly be your best choice for home use.

This will allow any one drive to fail and also allow you to add larger capacity drives later on.

If a video or a file becomes corrupt, I don’t need immediate access as long as there’s a backup available that I could use. Or is it good practice to use RAID so backups are available if files get corrupted?

• RAID is Redundancy ie. if one disk fails you're OK
• Backup is Backup ie. you have a copy of your data stored elsewhere in case your NAS fails or you find out a file has become corrupted.

You can either backup to the Cloud (most NAS include software for this) or take a backup of a subset of your most important data to some external USB drives. Either one-off snapshots or incremental backups.

Would I generally be better off by buying the enclosure + hard drives separately?

Quite possibly, depends on the deal you can get.

I understand the cost vs speed/efficiency argument of HHDs vs SSDs. What’s the typical life cycle for each? I don’t want to have to keep replacing them.

For a NAS (unless you have very specific needs) go with regular HDD. You'll be accessing the NAS over the network so that will somewhat negate the speed benefit of using SSD anyway. In short you wouldn't normally use SSD's in a NAS for storage — at least at this point in time/given their price.

There are some scenarios when a SSD 'cache drive' may be useful. But this tends only to be relevant if you have an application running on the NAS that itself needs quick access to a disk ie. access to a local database. For storage use just use standard mechanical HDDs.

Should I avoid certain branded hard drives and only consider certain ones? I've hard bad experiences with Seagate external hard drives before.

No, just ensure you are using some form or RAID redundancy (RAID 5 / SHR) so that if one drive fails (and one will eventually) you can swap it out without losing your data. This is what redundancy (RAID) gives you.

My feeling is get whatever is going for a good price and expect to replace the drives occasionally. You can go for HDD specifically for NAS or storage, which may have a higher level of warranty (and cost), but they too will eventually die. In short ensure you have redundancy and factor in the cost of having to replace a HDD in the next 5 years.

You'll often find that the larger retailers will have a deal on a particular brand/model of HDD at any one point in time, unless it's getting terrible reviews, I'd just go with whatever is the deal-of-the-month.

All mechanical hard drives fail eventually, there isn't some magical make, model or brand that is immune to this (obviously avoid any that get terrible reviews). But given you have redundancy make this work to your advantage, by not going on a unicorn hunt and paying silly prices for drives that 'promise' a better life (for 5 times the cost).

Finally, does the NAS have to be connected directly to the router or can it be elsewhere and connected by power line adapters?

Ideally you would, but even if you can't I'd run a ethernet cable along the skirting/under the carpet if possible, with power line adapters as a very last resort.

No suggestion re. suppliers, I'd search around for prices (once you know what NAS & HDD capacity/drives you're after) and stick to known suppliers Amazon, Broadband Buyer, Scan etc.

 

[jamieu]

Yep, that would be my aim however I'd like to keep costs down. Just had a look at Synology's C2 storage pricing and don't think I could justify that cost tbh.

Synology also works with AWS Glacier (Amazon Glacier) which may work out cheaper, but you pay more to retrieve you data. It will also take a long time to backup unless you have a very fast fibre connection or get them to send you a drive in the post. Or you could rent a LTO tape storage drive, but that not cheap and will only be a snapshot of your data, but may be an option if you just need a one time backup of your movie library as it stands.

You can obviously selectively backup certain volumes/folders – you don't need to backup everything.

Personally I'd just backup your Time Machine data, photos, music and important files, and live with the fact that you may have to re-rip all your movies if the whole NAS dies and ends up unrecoverable.

It's a trade off between cost and insurance, only you can make that call / work out how bad it would be if you lost certain subsets of your data vs the cost to back them up. The cost to back up a few thousand documents is pennies (so why not), but you may feel it's not worth paying out hundred of pounds per year to backup your movies, esp. if you can re-rip them in the worst case scenario.

RAID will give you redundancy from a HDD failure. But if you accidentally delete your files (without a backup) then they're gone. Likewise if your RAID hardware driver or NAS dies down the line you may be in precarious situation re. getting your data back — you can probably get the NAS rebuilt if parts are still available, but you may have a few sleepless nights.

 

[MaryWhitehouse]

Synology are compatible with Backblaze backup, their business (which I use for home) rates are very reasonable for large cloud backups but 32tb isn’t going to be cheap anywhere nor very practical for the first backup unless you pay (and Backblaze and others will) for a drive to be sent to you that you fill and return then they put in the cloud and you update.

 

[jamieu]

To be honest — if you absolutely have to have full backups of everything – one of the cheaper options might be to get two NAS units (one being a more basic model) and simply back up one to the other.

Doesn't deal with fire or theft, but would be much faster to recover than trying to download everything over an ADSL (or even an average fibre) connection. Also much faster to create the initial backup.

But my guess is you're going to have to be selective about what you backup and possible live with having to re-rip your movie collection in the worst case scenario.

Maybe you could do a one time backup to an large external USB drive of your most difficult to replace movies. Then backup everything else (TimeMachine, Photos, Music, important documents etc.) on a scheduled / incremental cloud based backup that will be much easy to both manage and stomach (cost wise).

 

[dhokes]

Hmm, thanks for all the replies. A lot to think about.

Something I'm still not completely sure about regarding RAIDs and redundancy vs. backups. So the former means that if I want to access a file and its on a drive (say driveA) that's corrupted, I would still be able to access the file instantly if driveA was part of a RAID setup, right?

If I don't need immediate access to the files i.e. my films/music, if I regularly backed-up the files on a separate hard drive (say driveB), then if driveA becomes corrupted, I could switch over to driveB, right? I understand it may take a few hours/days. Am I missing something here?

I think I need backups over redundancy i.e. a NAS to store/serve my files via. Plex which are backed-up regularly(?)

Could you have a NAS with the main drive (driveA) and that constantly backs up to the other drive inside the enclosure?

 

[MaryWhitehouse]

There's a crossover but in this situation I'd say redundancy is for your 'live' library so it doesn't fail so easily. Backups are for recovery if you do get a fail and take, potentially a lot of, time. For this amount of data I'd forget the cloud unless I had a lot of spare cash and make a mirror image on a second Nas.

 

[jamieu]

Hmm, thanks for all the replies. A lot to think about.

Something I'm still not completely sure about regarding RAIDs and redundancy vs. backups. So the former means that if I want to access a file and its on a drive (say driveA) that's corrupted, I would still be able to access the file instantly if driveA was part of a RAID setup, right?

Put simply RAID (or SHR which is Synology's version of RAID5) takes a bunch of separate hard drives and makes them appear a single 'virtual' volume. All you see is that one 'virtual' volume regardless of how many drive actually make up that volume [1]

If you use RAID5 (or SHR) then that 'virtual' volume will have redundancy baked in. Meaning you can lose a hard drive and everything carries on working — although you'll want to quickly replace the damaged drive as a second drive failure would mean total data loss.

Most NASs have 'hot swap' drives meaning once you replace the bad drive the NAS will automatically rebuild itself and go back to normal — although for 32TB of data this process can take up to a week, during which time you have to hope you don't lose a second drive. This is why in enterprise environments the quality of hard drives does come slightly more into play. For home use the chances of two drives dying in a week is extremely rare — again it's all about risk vs cost and how you balance it.

If you're using Synology then use SHR as they have taken all that is good about RAID5 and made it easier to use for everyday home use.

What you can't do is access each HDD individual once it is part of 'virtual' RAID volume.

[1] You can also split a single 'virtual' RAID volume into further 'virtual' volumes if you want. But the basic principle still stands. What you see is a 'virtual' volume, the physical underlying hard drives are (largely) invisible/inaccessible to you.

If I don't need immediate access to the files i.e. my films/music, if I regularly backed-up the files on a separate hard drive (say driveB), then if driveA becomes corrupted, I could switch over to driveB, right? I understand it may take a few hours/days. Am I missing something here?

Yes, just use an external USB hard drive if your data will fit — but don't try to backup from one bay to another inside the NAS [2]

This works well if you have a folder with say under 8TB movies (that never change) that you can copy to a single external hard drive — as a one time backup/snapshot (that you can then store somewhere safe).

Where you'll hit issue is if the top-level folders you need to backup (snapshot) are larger than your external hard drive. The easiest workaround there is to split/arrange your larger files (likely your movies and music) into top level folders ie. Movies c, Movies (1980-2021) so that they can easily be manually backed up to a single external drive each.

That's all fine for one time 'archived snapshots' effectively you just copying your files to a USB hard drive for safe keeping.

But for your everyday/ongoing backups ie. photos and files you probably want to use an automated/scheduled backup that i) takes a backup even night without your involvement and i) stores those backups in such a way that you can still retrieve a file that's deleted a week ago, even if a new backup has since run. Most backup software takes care of this part for you.

What most people do is take snapshot backups of their rarely changing archive data (ie. movies) and then use some form of Cloud backup service to automatically backup (and restore if needed) their regularly charging files — which are hopefully smaller in size than a huge movie collection.

[2] you could, in theory, backup drive 1 to drive 2 in your NAS but that isn't what people normally do and I wouldn't suggest it's something you do. Because automated backups normally keep daily, weekly and month versions, your backup drive would need to be larger that the drive you are backing up. You can mirror/replicate drive 1 to drive 2 — this is called RAID1 — but this is just redundancy, same as RAID5. If you delete a file from drive 1 it's also deleted from drive 2, so gone forever.

I think I need backups over redundancy(?)

You likely need/want both, especially if your backups aren't 100% automated.

If you're buying a 4 bay NAS then use SHR or RAID5 the cost of an extra disk is minimal compared to the hassle of having to rebuilt a NAS and attempting to restore everything form backups. I'd even go as far to say that running a NAS without 1-disk redundancy is largely defeating the point of buying a NAS in the first place.

Redundancy means everything carries on working, including your NAS itself. Backup means you have a backup — but only if you actually backed up your files and can restore them.

I put that last bit in bold as often people take a 'one time snapshot' backup and then carry on working as normal. Then realise they have lost a file or their hard drive has crashed only to find that the 'one time' backup was 12 months ago and/or can't be restored for some reason.

If you make backups then check you can restore them before you need to.

 

[mickevh]

RAID and backups mitigate different risks. "In business" we do both.

RAID avails continues access to data in the event of a disk failure. Backup provides point in time copies of the files that we can restore from in the event of files getting damage, lost or (if we keep enough generations) we can restore previous versions of a file if needed for any reason.

When you have a RAID array configured in a redundant configuration - which in the SOHO use case almost always mean RAID1 (mirrored) RAID5 (parity,) RAID6 (double parity) or proprietary systems that implement similar functionality - then when a disc dies the user population is completely unaware of anything as the data is still presented to them intact. "Someone" in IT will get a notification of the disc being dead, pull out the failed one, replace it with a new one and the array will (usually) automatically rebuild itself.

If, for whatever reason, we need to restore from a backup, let's envisage a catastrophic loss of an entire volume, then we would take the storage out of service and prevent anyone accessing it until IT has restored from a backup which is obviously a bigger impact on business operations than dropping a disc in a RAID set.

RAID has a big overhead in that a lot of storage is "lost" to provide the redundancy. For example, if you built a RAID1 set from 2x4TB discs, you've paid for 8TB storage, but "only" got 4TB usable. So for the SOHO use case, particularly a media tank, some argue that this is a waste of money as it's hardly critical that you can't watch Star Trek for a week while you re-rip from the DVD/DB titles that were on a deceased HDD. But of course, that's only OK since you have the original media. For anything that only exists on you NAS, you might want to safeguard it with RAID, backup, or both.

RAID5/6 are a bit less inefficient in "lost" storage than RAID1, but it's still significant.

There's nothing to stop you mixing and matching of course, say use non-RAID non-backup storage for the aforementioned media you have on DVD's and backup a volume for anything irreplaceable and a RAID set for anything you can't bear to be without for more than a few minutes (which many argue for SOHO isn't very much.)

It's complicated because a lot of this is "value judgement" and there's few "rules of thumb" I can give you as to what to do. I suggest the jumping off point is to holistically assess your data and determine how precious it all is in light of the sort of technologies we're been discussing and determine what is the best approach for you (including the cost.) Thence determine the risks you want to mitigate for each dataset.

To spitball an exemplar, if 24TB of your data is BD rips and 1TB is irreplaceable "valuable" data, you might determine that there's no point in a RAID set for the media (you can always re-rip it, but it'll cost you time,) and "just" backup the 1TB of valuable stuff to (say) cloud storage or USB stick or whatever once a day. There's endless permutations you could entertain, but start with assessing and categorising your datasets.

It is something of an IT truism that most data is static and doesn't change much, if ever. You might be surprised just how small the "working set" of data that is regularly changing (and thereby needing regular backups) is.

 

[dhokes]

Hmm, yeah like my mostly used/important files that I regularly use are stored in Dropbox/my computer. I don't actually use my videos on a daily basis, probably a few days a week. Guess it would be nice to have them all accessible.

For example, if I had 4x6TBs hard drives, what's the process to increase the space? Can I just buy a new drive i.e. 12TB and replace one of the 6TB ones? Or do they have to be the same size/paired with a same size? What happens to existing data on it?

Sorry for the questions!

 

[mickevh]

In "industry standard" RAID's it's technically not possible to dynamically expand an array, either "vertically" (swapping out the discs for bigger ones) or "horizontally" (adding extra discs to the array.) You have to back off the data, tear it down and rebuild from scratch. (RAID is a very old system.)

However, some RAID controllers can do this dynamically, including I believe the aforementioned SHR that some consumer NAS use, though others here are better placed than I to speak to that.

It will be a good idea to ensure you have "good" backup of at least any irreplaceable data before embarking such an expansion. But these days it seems to be a fairly robust and reliable process.

 

[jamieu]

Hmm, yeah like my mostly used/important files that I regularly use are stored in Dropbox/my computer. I don't actually use my videos on a daily basis, probably a few days a week. Guess it would be nice to have them all accessible.

For example, if I had 4x6TBs hard drives, what's the process to increase the space? Can I just buy a new drive i.e. 12TB and replace one of the 6TB ones? Or do they have to be the same size/paired with a same size? What happens to existing data on it?

Sorry for the questions!

Adding to Mick's post above, "industry standard" RAID doesn't allow this.

But Synology's SHR does, so you can just add a new drive and/or replace an existing one with a larger size one and it will (near) automatically rebuild the RAID volume for you.

Although for 32TB this can take from a few days to a week, during which you can still use your NAS, but performance may be impacted slightly and your redundancy may be affected.

 

[dhokes]

Thanks. Guess I need to figure out my ideal capacity!

 

[mickevh]

We should perhaps mention that whilst a RAID array is degraded and/or rebuilding, it is "vulnerable" to a second disc failure. Unlikely as it is, if horror of horrors it should occur, you'd loose everything unless you were running RAID6(like) which can mitigate a second disc failure.. One more reason to still make backups of at least the important data.

Of course, the bigger the discs are, the longer this "at risk" period is whilst any rebuild is occurring.

 

[dhokes]

We should perhaps mention that whilst a RAID array is degraded and/or rebuilding, it is "vulnerable" to a second disc failure. Unlikely as it is, if horror of horrors it should occur, you'd loose everything unless you were running RAID6(like) which can mitigate a second disc failure.. One more reason to still make backups of at least the important data.

Of course, the bigger the discs are, the longer this "at risk" period is whilst any rebuild is occurring.

Random question. If I purchase 4 hard drives from the same supplier at the same time, would they get 'used' the same amount in a RAID setup and therefore likely to fail at a similar time? Is it worth mitigating and if so, how? Using different brands? Buying from different places to increasing the likelihood of different manufacturing dates? Or is it not worth it?

 

[dhokes]

Also, having thought about it more, is the following setup and having separate drives easy to do out of the box with something like the Synology DS920+:

• driveA (use for plex)
• driveB (use for time machine + other data)
• driveC (backup driveA)
• driveD (backup B)

I know its not foolproof however it would be an improvement from my current setup. Are there any major disadvantages why I shouldn't do something like this?

 

[jamieu]

Also, having thought about it more, is the following setup and having separate drives easy to do out of the box with something like the Synology DS920+:

• driveA (use for plex)
• driveB (use for time machine + other data)
• driveC (backup driveA)
• driveD (backup B)

I know its not foolproof however it would be an improvement from my current setup. Are there any major disadvantages why I shouldn't do something like this?

Your backup drives C and D are unlikely to be large enough to take incremental backups of A and B (unless much larger drives) as the incremental backups will (ideally) be taking incremental daily, weekly and month backups, rather than a daily snapshot of changes — otherwise if you only find out today that you deleted a file two days ago and last nights backup has already run you'll gave no way to retrieve it (unless you are also taking weekly backups).

u less your taking incremental backups, what what your suggesting is RAID1 (mirroring) and hence still just redundancy - albeit less efficient in terms of disc space than RAID5 or SHR.


Personally I wound't use a NAS like you suggest. I'd keep the NAS as a single RAID volume (which is easy to expand) and then backup your data to a) external USB hard drives (for static / rarely changing data like your movie library) and b) use a Cloud based backup service on a regular schedule for (smaller) regularly changing data.

But no reason you can't do it as you suggest if you know the limitations.

btw. I can see you thinking re disc failure from same batch, but I think your probably overthinking it, discs fail for all kinds of reasons, so they won’t all fail within the sane week, even if there usage was 100% even - which it won’t be.

 

[mickevh]

Random question. If I purchase 4 hard drives from the same supplier at the same time, would they get 'used' the same amount in a RAID setup and therefore likely to fail at a similar time? Is it worth mitigating and if so, how? Using different brands? Buying from different places to increasing the likelihood of different manufacturing dates? Or is it not worth it?

There are those that argue for sourcing discs from different suppliers to mitigate the risk of getting a "bad batch" - but it tends to be people who are buying dozens/hundreds for a SAN solution (that's not a typo "SAN" and "NAS" are different things, albeit that there are similarities) rather than a (ahem) "little" file server with a few drives in it.

A counter argument is that mixing a set of different product could lead to performance that may not be optimal if (for example) one of the discs is significantly slower than the others. For example, you wouldn't want to mix 5400rpm and 7200rpm drives in the same array (some array controllers may not let you.)

Personally I wouldn't over think this for a SOHO media tank - such things are unlikely to be a big concern unless you want to get your inner nerd on and obsess over HDD performance "as a hobby." I'd buy from a reputable brand and pick a set of devices I likes the look of.

The sort of thing I would concern myself with is warranty period (some offer 3 years) and things like procuring drives that are designed for a NAS use case - eg. "always on." "high reliability" "low noise" etc (take you pick.)

Despite Internet Myths to the contrary, drives designs for different use cases are NOT "all the same but different prices" - "desktop" "A/V" and "NAS/Server" drives are different inside. For example, a high reliability "NAS" drive may have better error detection/correction than an "A/V" drive designed for a PVR or surveillance system where dropping the odd bit every 10 billion isn't such a big deal, a "desktop" drive might be designed to be quieter but have a bigger SSD/RAM cache built in.

Unfortunately, there's no simple answer to the question of how quickly a disc will wear out and/or go bad. Anecdotes make poor evidence, but I bought 4 discs about 5/6 years ago, one of then starting going bad within 18 months but soldiered on until just over 3 years (doh, just missed the end of the warranty) whereas all the others have been just fine. Same same in my "professional" hat - I've had jobs where we spun up servers that worked flawlessly for a decade and others that seemed to drop a disc every year. I suspect other IT pros would have similar tales to tell.

 

[jamieu]

Despite Internet Myths to the contrary, drives designs for different use cases are NOT "all the same but different prices" - "desktop" "A/V" and "NAS/Server" drives are different inside. For example, a high reliability "NAS" drive may have better error detection/correction than an "A/V" drive designed for a PVR or surveillance system where dropping the odd bit every 10 billion isn't such a big deal, a "desktop" drive might be designed to be quieter but have a bigger SSD/RAM cache built in.

I'd agree totally with this ^^^

What I think has changed is the price of hard drives. They used to be ridiculously expensive (at least for large capacity drives) so you ideally wanted them to last and/or be able to send them back if they failed for a (free) replacement. Nowadays it's often cheaper to go with standard/lower cost drives and factor in the fact you may have to replace them sooner (and pay for those replacement drives yourself out of warranty). But equally there's no guarantee that a drive specified for NAS use will last longer than a standard desktop drive.

For serious broadcast or surveillance use, where they are being read/written constantly there are good reasons to go with higher quality or faster drives. Ditto in enterprise environments you may want to pay out extra for that few % of extra reliability as you don't want to risk your RAID array failing on a 2nd drive while while rebuilding. Heat output, noise and (electrical) running costs are also all factors in the enterprise where you might have racks containing hundreds or even thousands of hard drives. But for SOHO home use these probably aren't factors you need to worry about – unless you have deep pockets and sleep terribly uneasily.

Anecdotally I think in ~8 years I have had two drives fail in my 14 bay NAS, which I don't feel is particularly bad. All standard desktop WD or Segate drives. Certainly cheaper than paying twice the price for 'enterprise drives' upfront. I would however avoid any 'bargain basement' drives or those where there seems to be an outsized number of negative comments — but bear in mind that all drives fail, so you will always have people writing negative reviews when they do.