[zfs-discuss] ZFS eating up all 16 GB RAM when combining 4k blocksize ZVOL with XFS
simar at gmx.net
Tue Nov 13 13:50:01 EST 2018
> What brings you to that conclusion? I didn't see anything in your post that really suggested any one explanation at all... Except generically, something consumed all the memory...
I am looking for a way to prove that or find whatever other cause there
First: That something is hidden. No easily accessible kernel or user
space stat shows it. So of course I can't point to what consumes all the
Second: This happens only when writing using explicitly libaio. Data is
written before that and there isn't anything remarkable. If I use
LIO/iSCSI from another machine with the same programs and XFS filesystem
it works. If I use SCST the target machine with the ZVOL crashes at the
same point, the second attempt to write to a file using 2MB chunks using
libaio. Of course that may be unrelated but it looks very suspicious.
Third: It also works with another ZFS implementation but the same
hardware and virtualization of the same minimal Ubuntu 18.04.1
installation on freenas. That makes it very unlikely in my opinion that
the problem is somewhere else in the Linux kernel.
So if you have any suggestions what test I could run to make sure it
isn't about Linux asynchronous writes and ZFS ZVOL please tell me.
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