ZFS gets stuck when copying large files #7241
Comments
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from the trace: looks like txg is stuck (txg_wait_open & txg_wait_synced)... and blkdev_issue_discard seems to be slow. |
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My experience maybe completely unrelated. I experienced a very noticeable slow down of write operations to my SSD pool when I ran master versions of ZOL that don't support TRIM last summer. I can see that you use these too now. |
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I have been studying this symptom for the last week or 2.. and it seems to consistent occur with several different kinds of virtualization, proxmox, xen, vmware, and virtualbox.. I also have seen that it is mostly described as being bad disks. These are high quality sas drives. Will look at trim too. On the systems I am working on I also just discovered this. 2018-03-14 05:04:47 lp_pool 255G 42.8G 0 276 0 24.2M The txg_sync hung at 5:04:50. It is stunning that the alloc and free change radically at 05:05:02. Can this just be an accounting issue with virtualized disks? Here is the trace |
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@behlendorf I finally got the code to the server, and was not able to reproduce this problem. |
System information
Describe the problem you're observing
I am running multiple kvm virtuals from zvols. When moving large amounts of data from one zvol to another, zfs stops writing data to all disks. There are no errors in
zpool events, syslog, or anywhere I could find in the host system. I was able to repeat the problem with the latest master (ZFS 0.7.0-338_g41532e5andSPL 0.7.0-29_g378c6ed.(Maybe) noteworthy points
sync=disabled( yes, I know this is dangerous and stupid... )zfs sendrunning fromssdtanktotankon the background, limited withpvto 10M/slog-disks on thetankpool was completely fullMy disk layout is as follows:
Include any warning/errors/backtraces from the system logs
result from
echo w > /proc/sysrq-triggerThe text was updated successfully, but these errors were encountered: