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ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
I have a ReadyNAS 104 device with 4 x 1 TB HDDs operating in a RAID 0 volume with Flex-RAID option. (Yes, I know RAID 0 is not reliable, this is kind of an intermediary storage and hot backup storage, and important data is backed up to the cloud.)
As one of the drives shows ATA errors, I'd like to replace it. I actually have 2 TB disks and a 4 TB disk. Can I just replace 1 out of the 4 disks with a 2 TB HDD and also enjoy the added storage? If I can, how can I do it? As RAID 0 is not reliable, I don't believe it has a copy of my data to restore from a hot swap, so I doubt I can just remove and swap the drive while the device is operating. Should I try to copy everything to an external storage first?
For the Samsung, I could not find accurate information, however it's recommended for desktop PCs, so probably they are not SMRs either.
Many (perhaps most) desktop drives in the 2-6 TB range are now SMR. That is one reason why I recommend either enterprise class drives or WD Red Plus or Seagate Ironwolf for ReadyNAS generally.
But as I said earlier, 1 TB drives are CMR. SMR allows 2-6 TB drives to have fewer platters (making them less expensive). New 1 TB drives typically only have one platter anyway, so SMR doesn't have any cost benefit. In any event, your disks are too old to be SMR.
With RAID-5 my experience was 2 MB/s, kind of USB2.
USB-2 disk speeds are typically 30-40 MB/s for large file transfers.
No way to tell now what the problem was. It could have been network-related or disk-related. It might even have been an issue on the PC you were using at the time.
Also, with mechanical disks, the speed does depend on what you are copying. The speeds I am giving are for larger files. If you are copying a folder full lot of small files (for instance, jpg photos), then the speeds are much slower. But RAID-5 read speeds should about the same as RAID-0.
SSDs don't have that problem, as there is no delay waiting for the data to reach the write heads for the platter. So if you want to maximize the performance, one option would be to get a single 2-4 TB SATA SSD, and set that up as a JBOD (single disk) volume. If that works well for you, you could add a second SSD (as a second volume) and retire the old mechanical disks.
Whether you use RAID redundancy or not, you should still have a backup plan for your data - RAID isn't enough to keep it safe. And without RAID redundancy you do need to have another copy in order to deal with disk replacements (either failures or expansion in capacity).
I guess once or twice I could see 50 MB/s, but the usual rate was not higher than 20 MB/s on 5e UTP cables capable of a lot more. Disk tests run regularly, and only the drive I plan to replace shows ATA errors (I don't know if 105 ATA errors is high or not).
The RN100 series can't keep up with gigabit ethernet (which would be about 100 MB/s). As noted above, the speed does depend on what you are copying.
You say "cables". Are you using both NIC ports in the NAS? That can be a factor if you don't know how to set that up properly. I don't recommend connecting them both - the RN100 series can't keep up with a single gigabit connection, so there is no benefit.
I'd consider 105 ATA errors to be concerning myself. But it does depend on the details - in particular whether the counts are regularly rising or not.
Re: ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
Thanks for your reply, @Sandshark! What if I happen to replace two 1 TB disks with 2 TB disks? Still unable to use the extra space? I know the table in the UG for X-RAID describing how much disks to replace to gain extra capacity, but there's no such table for Flex-RAID, and there's also a note that RAID 0 cannot be vertically expanded, that's why I'm so confused.
Converting the system to a different RAID (if I can do it on-the-fly at all) is not really an option, as I experienced very-very bad performance with other RAID levels, something like a few MB/s R/W speeds, or even less than 1 MB/s.
You can replace the failing five with a larger one, but you will not gain any additional space.
True with RAID-0.
But if you set up a one-disk volume as jbod, you can then concatenate additional drives- they end up in one volume, but they are not striped like RAID-0. So I think the disks can be of unequal size if you do that.
Re: ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
"Vertical expansion" is what you are asking if you can do, and the answer is as you have already determined -- it can't be done. Picture the drives laid out in a row. "Horizontal expansion" is adding another drive. "Vertical expansion" is making one (or more) of them "taller" (larger). As @StephenB has said, there are formats that will allow future expansion, but you're going to have to back up the data, start over, and then restore your data to go there.
Converting the system to a different RAID (if I can do it on-the-fly at all) is not really an option, as I experienced very-very bad performance with other RAID levels, something like a few MB/s R/W speeds, or even less than 1 MB/s.
what drives were you using?
Very slow speeds are usually a result of
accessing the volume while it is resyncing
a failing disk
using SMR disks (shingled magnetic recording)
The RN104 is slow, but you should be seeing speeds in the 50-75 MB/s range for large file transfers.
As @Sandshark says, you cannot convert or expand RAID-0 on the fly.
Re: ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
Well, it includes
1 x WDC WD10JPVT-75A1YT0
2x SAMSUNG HD103SI
1x WDC WD10EADS-22M2B0
The WDC disks are not SMRs for sure. For the Samsung, I could not find accurate information, however it's recommended for desktop PCs, so probably they are not SMRs either.
I guess once or twice I could see 50 MB/s, but the usual rate was not higher than 20 MB/s on 5e UTP cables capable of a lot more. (Nowadays I can access it via WiFi, so it's inherently limited to 12-15 MB/s.) Disk tests run regularly, and only the drive I plan to replace shows ATA errors (I don't know if 105 ATA errors is high or not).
With RAID-5 my experience was 2 MB/s, kind of USB2.
Does any of the above tell you anything new or interesting?
For the Samsung, I could not find accurate information, however it's recommended for desktop PCs, so probably they are not SMRs either.
Many (perhaps most) desktop drives in the 2-6 TB range are now SMR. That is one reason why I recommend either enterprise class drives or WD Red Plus or Seagate Ironwolf for ReadyNAS generally.
But as I said earlier, 1 TB drives are CMR. SMR allows 2-6 TB drives to have fewer platters (making them less expensive). New 1 TB drives typically only have one platter anyway, so SMR doesn't have any cost benefit. In any event, your disks are too old to be SMR.
With RAID-5 my experience was 2 MB/s, kind of USB2.
USB-2 disk speeds are typically 30-40 MB/s for large file transfers.
No way to tell now what the problem was. It could have been network-related or disk-related. It might even have been an issue on the PC you were using at the time.
Also, with mechanical disks, the speed does depend on what you are copying. The speeds I am giving are for larger files. If you are copying a folder full lot of small files (for instance, jpg photos), then the speeds are much slower. But RAID-5 read speeds should about the same as RAID-0.
SSDs don't have that problem, as there is no delay waiting for the data to reach the write heads for the platter. So if you want to maximize the performance, one option would be to get a single 2-4 TB SATA SSD, and set that up as a JBOD (single disk) volume. If that works well for you, you could add a second SSD (as a second volume) and retire the old mechanical disks.
Whether you use RAID redundancy or not, you should still have a backup plan for your data - RAID isn't enough to keep it safe. And without RAID redundancy you do need to have another copy in order to deal with disk replacements (either failures or expansion in capacity).
I guess once or twice I could see 50 MB/s, but the usual rate was not higher than 20 MB/s on 5e UTP cables capable of a lot more. Disk tests run regularly, and only the drive I plan to replace shows ATA errors (I don't know if 105 ATA errors is high or not).
The RN100 series can't keep up with gigabit ethernet (which would be about 100 MB/s). As noted above, the speed does depend on what you are copying.
You say "cables". Are you using both NIC ports in the NAS? That can be a factor if you don't know how to set that up properly. I don't recommend connecting them both - the RN100 series can't keep up with a single gigabit connection, so there is no benefit.
I'd consider 105 ATA errors to be concerning myself. But it does depend on the details - in particular whether the counts are regularly rising or not.
Re: ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
Thank you for the many valuable information. And you are very right, it's just so simple, I don't need to consume that much electricity of having 4x1TB disks, or 1x2TB and 3x1TB when I can just insert 2x2TB for the same capacity after backing up everything from the drives. Some slots may well remain empty.
I guess the only thing I should pay attention to is to pause cloud syncing to ReadyCloud before starting the operation, and re-create the new volume with the same name, so it won't start to upload a whole new copy of my data, but it will be able to resume syncing.
Re: ReadyNAS 104 x Flex-RAID x RAID 0 -- replace one disk with larger?
God, I look like an idiot. 😄 I must confess I always mixed up ReadyCloud with ReadyNAS Vault. I use this latter and it works properly as far as I can tell – time to time I check what's there and it seems it synchronizes as requested. To me it's cloud, too: it's the computer of someone else. 🙂
