[lustre-discuss] Synchronous writes on a loaded ZFS OST

[Dilger, Andreas]

> On May 15, 2018, at 10:05, Steve Thompson <smt at vgersoft.com> wrote:
> 
> On Tue, 8 May 2018, Vicker, Darby (JSC-EG311) wrote:
> 
>> The fix suggested by Andreas in that thread worked fairly well and we continue to use it.
> 
> I'd like to inquire whether the fixes of LU-4009 will be available in a future Lustre version, and if so, when it is the likely release date. My installation (2.10.3) is severely affected by the fsync() issue, and I'd like to patch it as soon as possible. TIA,

There is no active development on LU-4009 ("Add ZIL support to osd-zfs")
so there is no ETA.

The only available workaround is LU-10460, which can be enabled with either
a module parameter:

    options osd-zfs osd_txg_sync_delay_us=0

or at runtime via:

    echo 0 > /sys/module/osd_zfs/parameters/osd_txg_sync_delay_us

This is available out-of-the box in Lustre 2.11 and Lustre 2.10.4 (when it is
released, which should be soon), or you can download and build b2_10 today.

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel Corporation