I'm hoping someone can help me troubleshoot my OOM error. I'm running a secondary unRAID box as a backup for my main server. I mount a share ("Backups") from the secondary box on the primary server via Unassigned Devices. Then I'm trying to get my backup routine stable and automated using an rsync script via the User Scripts plugin. The rsync script keeps failing with IO errors so when I checked the logs on the backup server, it shows Out Of Memory errors and invoking OOM-Killer on SMBD. I'm lost as to how to further hunt down the source of the error and correct it.

I am not currently running anything else on the backup box. There are no VMs and I have even disabled docker completely. I would love any insight anyone can provide.

 

Diagnostics:

vault-diagnostics-20200618-0655.zip

FWIW, I have now tested with disk writes in both the standard "read/modify/write" and turbo "reconstruct write" modes, as well as with parity disabled. From what I can tell, it seems that the issues are related to the parity calculations and writing parity as the issue does not occur when writing to the array with parity disabled. Obviously, I don't want to run the array with parity disabled as a solution.

Any further insight or suggestions would be welcome.

1.7GB is very little RAM to run Unraid v6 even as a basic NAS, it should be fine with 4GB.

7 hours ago, johnnie.black said:

1.7GB is very little RAM to run Unraid v6 even as a basic NAS, it should be fine with 4GB.

Thanks for the input. I was starting to wonder if I would need to add more RAM. I figured since the wiki says 1GB is adequate for basic NAS function, I should be fine. I'll scrounge around and see what I can find to bulk up the RAM.

Maybe the wiki is out of date because when I boot unraid fresh it uses 900 something mb of ram before I even do or turn anything else on. To actually do anything needs a bit of ram on top of that. 

3 hours ago, mikedm139 said:

I figured since the wiki says 1GB is adequate for basic NAS function

That was true once, but not for some time, it should be updated.

1 hour ago, johnnie.black said:

That was true once, but not for some time, it should be updated.

I've edited the Overview entry to say that 2GB is now the minimum for basic NAS services but that even for that 4GB is recommended.

 

We will need to keep an eye on whether the new features coming with Unraid 6.9.0 will mean that 4GB becomes the minimum requirement even for basic NAS features.

I'm having this issue with 12GB of RAM on the destination Unraid server. I have 64GB on the source Unraid server. Just a simple "rsync -avXP" on 3.8TB worth of data.

 

Quote

Nov  7 21:34:55 MediaUnraid kernel: Out of memory: Killed process 18118 (smbd) total-vm:15371796kB, anon-rss:10953916kB, file-
rss:4kB, shmem-rss:14624kB, UID:1000 pgtables:22252kB oom_score_adj:0

 

Oddly when I exclude (with --exclude) the files that cause the OOM error, it runs fine for a few more hours. So it seems like this is happening with specific files rather than for RAM limitation reasons. Also, when I take a look at the destination RAM usage, it's only 67% when it happens. 

 

Any clues?