Jump to content
NAS

Stopping docker img causes array wide spin up

12 posts in this topic Last Reply

Recommended Posts

unRAID OS Version: v6b8

 

Description: Stopping docker img causes array wide spin up

 

How to reproduce: With array disks spun down, and img file on the cache drive set as a cache only share, stop the docker img and watch every array disk come up

 

Expected results:  Actions on an image file on a cache disk should not have an array wide effect

 

Actual results: All disks come up

 

Other information: Stock v6b8 except cache_dirs. At a guess we are issuing a SYNC when closing the img file which i believe is system wide.

Share this post


Link to post
At a guess we are issuing a SYNC when closing the img file which i believe is system wide.

 

That is correct.  Do non-reiserfs array disks also spin up?

Share this post


Link to post

I currently dont have any non reiser disks in this array other than the cache drive and my other test system has a broken USB.

 

Can someone else confirm?

Share this post


Link to post

I now have a mixed array of reiser and xfs disks and I can confirm that when I stop a docker container, if the array disks are spun down ONLY the resier disks spin up.

 

Is this a known issue or a config specific problem?

Share this post


Link to post

Any thoughts on this. Best case scenario is that it is PEBCAK but it doesnt seem to be obvious if it is. The only thing I can think off I do differernt than "some" is I often use "/mnt/cache" rather than "/mnt/user/" although I dont see why this would cause spin up on.

 

As an illustration here is a before and after performing a single docker container stop. Notice the parity come up as well. Comparing write counts before and after (sorry I edited them out by mistake) I can see most of the RFS disks write count increase by 7 or 8. I am wondering if this is some sort of spin up caused by the docker container issuing a disk flush such as SYNC and RFS handing that differently than XFS.

 

This is really annoying so any insight would be very much appreciated.

 

before.thumb.jpg.4f3e4d7abf5dc2f2bd00a57934aa503c.jpg

 

after.thumb.jpg.6edbfeed74b6af8af23ee55c9fc24ceb.jpg

Share this post


Link to post

Which unRAID version are you running?

 

Share this post


Link to post
On 4/25/2018 at 9:51 AM, NAS said:

I now have a mixed array of reiser and xfs disks

 

Unfortunately this is a defect with the way ReiserFS sync is handled.  Actually the way file system sync is handled in the kernel has undergone several changes over the years and back when ReiserFS development stopped (you know why) kernel developers only made changes to keep this legacy FS "running" but without refinements really.

 

If you don't mind we should close this topic.

Share this post


Link to post

Great. Its non ideal but at least now I know. I honestly have been wracking my brains what I was doing wrong. Time for me to move to XFS completely then.

 

Lets close as resolved. Appreciated.

Share this post


Link to post

Aha! This answers a long-standing issue no one could diagnose. Why my array disks all spin up round robin when I stop or restart a docker. I am still all ReiserFS for data disks.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.