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Sound good. Just a last question, I guess. Since I have one slot (out of 4) free I thought I could mount it there first and perhaps make some check, before I use it to replace one of the RAID-disks. Is that a reasonable idea? Perhaps make disk test of this new disk?
Personally I always test my disks in a Windows PC using vendor tools (Lifeguard for Western Digital; Seatools for Seagate). I run the long non-destructive test, and follow that up with a full erase / write zeros test. I have had some disks that pass one of those tests, but not the other - and I have sometimes found failures with just-purchased disks.
The NAS will do the short SMART self-test before it adds the disk to your volume. If you can't test the disk in a PC, then you could insert the disk the 4th slot, create a volume on it, and then run a disk test on that volume. Then destroy the volume, format the disk, and remove it. After that, hot-swap with the disk you want to replace. (Note that if you were running XRAID you couldn't do this).
FWIW, I suggest you reconsider your use of FlexRAID. You can make a full backup, and switch to XRAID (reconfiguring the NAS and restoring the data from backup). You'd have the same amount of storage as you have now - just on one volume. Expansion in the future would be a bit simpler.
My idea is to just for safety right now incrase one 4TB to 8TB disk in the RAID-1.
And in a year or so take the next disk and really get volume expansion.
What maintenance is important to do just before doing the expansion?
The most important thing is to back up your data before you start. If you don't have the capacity to do a backup, then take care of that before you invest in new internal disks. Your volumes (or the NAS itself) can fail at any time w/o notice. The way to protect your data is to back it up.
As far as the maintenance tasks go, personally I don't tie them to expansion. I run all 4 maintenance tasks on a monthly schedule - currently I just schedule one test per month in the maintenance schedule in the volume settings wheel. That said, it wouldn't hurt to run the disk test on the RAID-1 volume before you replace one of those disks. Perhaps check the SMART stats before and after the test, and see if any of the counts have changed.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
On the System/Performance page, hover over the green dot beside the drive type and a pop-up will show you the SMART data. If you click in the pop-up, it'll let you scroll in it.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Now both RAID-1 disks and also single JBOD disk have been tested and no faults found!
Slightly surprise the difference in 200 power-on hours for the RAID-1 pair, but it has happened a few times over the year when they needed a re-sync and that may change the balance. I am not sure. Or they start-up and close-down slightly differently which just accumulates.
I guess a "scrub" is a good idea to do on the RAID-1 pair before exhanging one of them?
Is there any small difference if one choose diska 1 or disk 2 to exchange for the larger 8TB also 5400 rpm disk? Recall vaguely that the firm-ware is on only one of them, but nut sure at all. But there is some small odd difference in the Ready NAS design, or am I wrong?
Re: Maintenance needed before horizontal expansion of Flex-raid-1
As an aside, I am wondering why you chose FlexRAID when you set up the NAS. X-RAID with 3x4TB would have given you an 8 TB volume - the same space you have with FlexRAID.
Recall vaguely that the firm-ware is on only one of them, but nut sure at all. But there is some small odd difference in the Ready NAS design, or am I wrong?
The firmware is actually on all three disks. Apps and home folders are on the data volume, so they are on both disks.
I guess a "scrub" is a good idea to do on the RAID-1 pair before exhanging one of them?
I don't see the need (and wouldn't do it if I were in your shoes).
Ditto. A scrub from the GUI does a BTRFS scrub and an MDADM re-sync simultaneously. So, it's even more stressful on the drives than a re-sync for a drive replacement. If one drive is near failure, that might push it over the cliff and you'd know it's the one that you should replace first. But it could harm the volume when it did, or even push both over.
I guess a "scrub" is a good idea to do on the RAID-1 pair before exhanging one of them?
I don't see the need (and wouldn't do it if I were in your shoes).
Ditto. A scrub from the GUI does a BTRFS scrub and an MDADM re-sync simultaneously. So, it's even more stressful on the drives than a re-sync for a drive replacement. If one drive is near failure, that might push it over the cliff and you'd know it's the one that you should replace first. But it could harm the volume when it did, or even push both over.
Plus the disk tests you just finished show that all sectors of the existing two drives can be read. Which is enough to sync the new disk when you insert it.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Bit-rot protection is a ReadyNAS feature that uses a combination of BTRFS checksums and RAID redundancy to repair files that silently change (e.g. experience "bit rot"). It's not directly related to scrub.
Scrub is a useful maintenance function - I do run it every 4 months on schedule, and I believe @Sandshark also runs it periodically. I just don't think that you need to run it before doing your disk upgrade - the disk test you've already run is sufficient.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Sound good. Just a last question, I guess. Since I have one slot (out of 4) free I thought I could mount it there first and perhaps make some check, before I use it to replace one of the RAID-disks. Is that a reasonable idea? Perhaps make disk test of this new disk?
Sound good. Just a last question, I guess. Since I have one slot (out of 4) free I thought I could mount it there first and perhaps make some check, before I use it to replace one of the RAID-disks. Is that a reasonable idea? Perhaps make disk test of this new disk?
Personally I always test my disks in a Windows PC using vendor tools (Lifeguard for Western Digital; Seatools for Seagate). I run the long non-destructive test, and follow that up with a full erase / write zeros test. I have had some disks that pass one of those tests, but not the other - and I have sometimes found failures with just-purchased disks.
The NAS will do the short SMART self-test before it adds the disk to your volume. If you can't test the disk in a PC, then you could insert the disk the 4th slot, create a volume on it, and then run a disk test on that volume. Then destroy the volume, format the disk, and remove it. After that, hot-swap with the disk you want to replace. (Note that if you were running XRAID you couldn't do this).
FWIW, I suggest you reconsider your use of FlexRAID. You can make a full backup, and switch to XRAID (reconfiguring the NAS and restoring the data from backup). You'd have the same amount of storage as you have now - just on one volume. Expansion in the future would be a bit simpler.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Thanks for your detailed advice here of testing the disk first and how to procede! I plan to do it on the NAS in the 4th empty slot, since I have no PC available to put the disk in.
When the testing is done and provided the disk ok, you think it is better to hot swap the disk to the RAID-1 volume I have? To me it sounds "safer" to turn the NAS off and then swap and let it boot with the new disk in the RAID configuration and then let it synchronize which may take a number of hour or a day or so. But still I understand that hot swapping is possible if necessary, perhaps even have some advantage over "cold swapping"?
About my configuration and reasons for it. The first volume two-disk RAID1 is for archive, photos, music, documents etc. The second one-disk JBOD volume is for backup of our computers in the home office. This volume in encrypted. We also do backkup of ther office computers on external USB as complement about twice a month or so. NAS take the regular backup and use macOS Time Machine here. So I a bit prefer to have separate volumes for this reason.
A (perhaps dated) technical reason to stay with RAID-1 is that it is what I understand technically easier than RAID with more disks and less redundancy. When I set the NAS up BTRFS was rather new for Netgear and I understood it as they took a bold technical lead here. Other NAS vendors have hesitated. Still at the time, here was uncertainty around how mature the "software" RAID in BTRFS was. Educated people told me that in professional use you really have hardware RAID and was sceptical here. So play it safe I stayed with RADI-1. Today, several years later I guess software RAID with BTRFS in ReadyNAS and perhaps also some other Linux vendors use it. I have not seen any alarming reports here, but I have not really looked for it either. Here is some recent talk from QNAP that question BTRFS snapshot etc but that is another story.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
It is better to hot swap. That way, the NAS does not have to figure out what's going on when it boots with a degraded volume. You will see in the log that it saw the removal and insertion. NAS are built for that.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
I have followd the detailed instruction by StephenB on page 13. So far everything goes as expected. I am now re-syncing and down 8 % in 6 hours. The original disk is 4 TB and it had about 3.3 TB data. This will take about 3 days. I just wonder if it is a good idea to just let it go on in a stretch - or good to shut down and restart next day, or so. Looking at performance heat looks ok 51 C for the new 8TB and 48C fo the old 4 TB and 41C for the almost in-active disk 3 that is also 4 TB.
Is it good to let the system rest a few hours - or is the sync then needed to start from scratch - more or less?
@janpeter1 wrote: I have followd the detailed instruction by StephenB on page 13. So far everything goes as expected. I am now re-syncing and down 8 % in 6 hours. The original disk is 4 TB and it had about 3.3 TB data.
Resync is resyncing the full 4 TB - mirroring every sector of the remaining 4 TB disk to the replacement. It doesn't matter how full the disk is - unused sectors are also mirrored.
Looking at performance heat looks ok 51 C for the new 8TB and 48C fo the old 4 TB and 41C for the almost in-active disk 3 that is also 4 TB.
You can set the profile to "cool" - I sometimes do that when syncing (setting it back to balanced when done). Temps vary a lot in different disk models.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Thanks! Put it on cool and temperature dropped a few degrees. And yes you here the fan a bit. Before only in quiet mode, so a difference. I let it just go on now. Thanks again.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
Mission completed! No problems. It all went faster when I increased the coolling and the whole sync of 4 TB to the new 8 TB disk took about 24 hours.
I understood that problems with a new disk turns up usually immediately or very early. I just wonder if my old former 4TB RAID-1 disk if there is any use to keep it for a while as is? I have sveral USB-backups so that is no real problem. Later I plan to erase this old 4TB disk and perhaps keep is a cold or hot spare.
Re: Maintenance needed before horizontal expansion of Flex-raid-1
The old RAID1 drive can be used to boot the NAS as it was immediately prior to it's removal if it was removed prior to any horizontal expansion. If it was after, it's not really going to help you with anything.
