So I'm curious to what if any recommendation exists for setting up Volume Maintenance? The only timeline given by the software manual was for scrubbing: Scrubbing cleans and validates all data on a volume and checks the volume for errors. No data is deleted. Folders, LUNs, and snapshots on the volume remain intact. Scrubbing every six to eight weeks is common.
The options are as follows below and the manual doesn't really talk about Disk Test other than it's an option when setting a schedule.
Defrag Balance Scrub Disk Test
Are others using Bit-rot? From the manual: Bit rot protection is available for any folder stored on your ReadyNAS system. On higher-end models it is on by default. Bit rot protection can slow the performance of a system and increase fragmentation, and so is not on by default on lower-end models.
I presume if Bit-Rot isn't used than routine defragmentation wouldnt' be required? I'm guessing the 626 is a lower end NAS since it wasn't on by default but even so I'm uncertain how much I would really need it.
I'm guessing the 626 is a lower end NAS since it wasn't on by default but even so I'm uncertain how much I would really need it.
The 626X is at the top of the line of course. Perhaps the manual needs a bit of updating.
Bit-Rot protection is a proprietary netgear feature. "Bit-Rot" occurs when files somehow get corrupted on the disk. The bit-rot protection uses the parity info plus the BTRFS file checksum to recover the file data. The odds of bit-rot on an RN626X are lower than most consumer-NAS because it uses error-correcting RAM.
Enabling Bit-Rot protection also enables CoW all the time.
That's good feedback as usual. I believe you have a 526 so do you use Bit-rot and if so was there a significant performance hit? I didn't have it turned on when I moved all my data to the new NAS and from what I read it would only help with new files written to the NAS. So I guess the protection would be limited? As for the other tests, I was going to run the defrag/balance twice a month and the scrub (which takes forever) 3 times a year. I dont' really know what the disk test does or if it's necessary as their is no explaination given in the manual.
That's good feedback as usual. I believe you have a 526 so do you use Bit-rot and if so was there a significant performance hit?
It's not turned on in my RN102 and RN202 (both are jbod, so it doesn't really apply). The RN526 isn't really set up yet - I'm still kicking the tires on it. It's on at the moment, and I'm planning to leave it on.
I didn't have it turned on when I moved all my data to the new NAS and from what I read it would only help with new files written to the NAS. So I guess the protection would be limited?
It should work on all the files in the shares where it's turned on (even if it is turned on after files are written to the share).
Got it on Bit-rot and I intend to do some testing here using a dummy share and files to see what if any hit the 626 takes. I'm sure there is some degration but I'm still not convinced it's needed given my use. Although, if the performance hit is negligible I may just leave it on for added insurance. Especially on files that are rarely accessed such as old pictures/videos. You wouldn't happen to know how long that disk test runs? It probably varies per disk and array size but just ballpark would be enough of an idea. I'm unable to run it manually (unlike defrag/balance/scrub) but I could set the schedule so that it runs instantly. And get that 526 up into production already as this forum is depending on you! You're like a one man team on here and for the most part one of the few that reliably responds to my post regardless of which section I post in.
We link enabling/disabling bit-rot protection to enabling/disabling CoW. The GUI option is set at the share level. So one share could have bit-rot protection enabled and another have it disabled.
Defragmentation breaks the CoW link between current data and snapshots, but it doesn't uncow a file.
CoW should not be used where there are a huge number of modifications made in place to files.
Got it on Bit-rot ... but I'm still not convinced it's needed given my use.
As mdgm says, some shares definitely shouldn't use it (or snapshots). Torrent download folders is one example - the file is updated every time a block is received, and that creates a lot of fragmentation.
As far as overhead goes, if there are no errors the main overhead is computing the btrfs checksums when data blocks are written and verifying them when data blocks are read. I doubt if you'd see any impact on your 626X unless you are using 10 gbit (and maybe not even then). Though its worth testing.
We link enabling/disabling bit-rot protection to enabling/disabling CoW. The GUI option is set at the share level. So one share could have bit-rot protection enabled and another have it disabled.
Defragmentation breaks the CoW link between current data and snapshots, but it doesn't uncow a file.
CoW should not be used where there are a huge number of modifications made in place to files.
Ok, the only share where there is a number of modifications going on is the backup share for my PCs and other files. The rest would be photos/vidoes/etc which sounds like may benefit from Bit-rot.
Got it on Bit-rot ... but I'm still not convinced it's needed given my use.
As mdgm says, some shares definitely shouldn't use it (or snapshots). Torrent download folders is one example - the file is updated every time a block is received, and that creates a lot of fragmentation.
As far as overhead goes, if there are no errors the main overhead is computing the btrfs checksums when data blocks are written and verifying them when data blocks are read. I doubt if you'd see any impact on your 626X unless you are using 10 gbit (and maybe not even then). Though its worth testing.
Yup, that makes sense and I'm not running Torrent so no worries there. I'll test it either way once I get some time here.
