Ugrading to 10 TB drives

[ROLLINS]

I am using raid 5 with four 5 tb drives.Any idea How long will the rebuild take?
I still have almost 3 tb before i run out

[dolbyman]

depends on disks (new and old) and device speed

could take anywhere from <20 hours up to several days per disk, and the subsequent expansion will also take some time

[ROLLINS]

Oh ok, that's a long time where anything can happen

[kherr4377]

I always opt for a fresh start, restoring from backups. less wear and tear on the drives, especially the ones your replacing ...

[ROLLINS]

Yea that's the thing i never did get around to having complete back,think i will do the rebuild one every couple of days

[P3R]

Oh ok, that's a long time where anything can happen

Let's say that a disk replacement takes 24 hours, that's a very insignificant time in relation to the normal limetime of a disk. Therefore I'd say that the rebuild time, as long as it's not counted in many weeks, contribute very, very little to the risk for a faulty disk.

During a rebuild all other disks need to be read, every byte from start to finish. If that complete read is done over 10 hours or 100 hours doesn't really matter. It's much more likely that the disks have already developed a problem (that you will be made aware of during the rebuild) than that the complete read itself is causing the problem.

Other than the performance degradation (which in some professional applications can be a huge problem) the issue with long rebuild times is mostly that administrators are so worried about them when their worries should be elsewhere.

If you've done the recommended regular RAID scrubbing, the risk for a failure during the expansion is very small. If you haven't done RAID scrubbing, there's a higher risk but the rebuild time is extremely unlikely to affect it.

What you should worry about is your lack of backups, that's a much worse risk and that exist now even before you start the rebuild.

[CiASpook]

I have done this prosedure many times over the years. From 8x 2TB -> 4TB -> 6TB -> 8TB -> 10TB and migrated from several systems by moving drives. Never failed. But when I went from 10TB -> 14TB I had to do a data migration due to I had to upgrade filesystem to be able to use Qtier. So I scratched my setup and restored everything from backup. Took some time. At 99,96TB usable space now.

Another thing do consider as your drive sizes increase and subsequently rebuild times also you should consider RAID6 for critical data.

But, always have good backups.

[ROLLINS]

First one took 11 hours, then i went in change the priority, rest took 9 hours

[ROLLINS]

Think i going to run out of space before 20 TB drives are on the market
Don't want to change from Raid 5

[P3R]

Think i going to run out of space before 20 TB drives are on the market

That's because you let yourself be limited by a too small NAS compared to your storage demands. Buying the largest disks available is expensive and replacing working disks (that was expensive when you bought them) will over time be costly.

Consider replacing the NAS with an 8-bay chassis instead. Yes they're more expensive than a 4-bay but you'll avoid spending as much on the disks. If you migrate your current disks to an 8-bay you should be able to increase or even double your storage with 4 more 10 TB disks (that will be much less expensive than 4*20 TB disks).

Don't want to change from Raid 5

Risk increases with storage capacity so you really should plan for a migration to RAID 6 when doing the next significant storage expansion.

Hopefully you at least have an external backup of your most valuable data. If not, that's your largest problem instead of how to expand the NAS further.

[ROLLINS]

I just looked at one of the qnap 8 bays wondering why it cost way less than my 4 bay..Will do more digging.
Thanks for the advice,i should have gone with an 8 bay form the start.You're right looking back at it when i bought the
10 TB drives their totals are more than what an 8 bay cost and that's just over a year i think. At that time weren't even considering
an 8 bay

[scolumbo]

This is what I did. I started years ago with a 4-bay (TS-451) with 4x4 TB in Raid 5. When I realized I needed more storage, with advice from this forum, I bought an 8-bay (TS-853A) with 6x10 TB in Raid 6. I now use the TS-451 as a backup for my most valuable data along with several external drives that are stored off-site. It gives me a decent backup system and I still have room to add more disks as needed.

[ROLLINS]

What is your advice should i get the 4 drives now or get the 8 bay first.I am asking because i read somewhere on here all drives
should be same brand and model.Those 10 TB may be hard to find soon

[dolbyman]

as long as the drives all have the same specs (so no slow drive is dragging the array speed down) make and model dont matter

[P3R]

I am asking because i read somewhere on here all drives should be same brand and model.

I'd say that's a myth. If all disks are compatible NAS or Enterprise disks, don't worry about mixing. I frequently mix disks in RAID arrays and never had any problems with that. I use three different models of two different brands in an 8-disk RAID 6 array and it's been very reliable.

The only thing to be aware of is that the array speed will always be limited by the slowest disk so it won't be optimal for performance to mix slower spinning (5400/5900 rpm) or very old disks with faster (7200 rpm) and or new disks.

Those 10 TB may be hard to find soon

Buy 12 TB or whatever larger size is available when you need them. Of course only 10 TB on the larger disks will be used but this will also be a way to slowly expand the storage as when all disks are replaced to the larger larger size you can expand the array to make use of the last TBs on all disks.

The 8-disk array I mentioned above that I have consist of 5*2 TB and 3*3 TB disks and when the older 2 TB disks fail I will replace them with 3 TB (or larger) disks.