We are using Direct IO to slow mkfs and therefore lower I/O load. I'm
not aware of a way to directly ask mkfs to reduce the I/O load or work
more slowly. Using ionice at idle priority would be ideal, but we are
using the mq-deadline scheduler rather than bfq or anything. I
understand ionice is a noop under the deadline scheduler.
In this case we want the mkfs to be lower priority that other tasks,
e.g. other XEN guests. And sometimes we are creating large filesystems
on spinning disk.
I haven't seen OOM situations with mkfs lately.
I picked this up when running tests on bullseye. So far I've only run
the tests on image (loopback) files, but mostly we create new
filesystems on new lvm logical volumes; I see we use the same -D flag
there and expect the same fault.
I see e2fsprogs is 1.46.5 is in bullseye-backports, so in the absence of
a stable fix or a better way to reduce load we'll probably use that.
Thanks,
Alex
On 11/08/22 15:43, Theodore Ts'o wrote:
I'm just curious --- what is your use case for wanting to use Direct
I/O in mke2fs?
