On Thursday, July 21, 2016, Mike Christie <mchri...@redhat.com> wrote:
> On 07/21/2016 11:41 AM, Mike Christie wrote: > > On 07/20/2016 02:20 PM, Jake Young wrote: > >> > >> For starters, STGT doesn't implement VAAI properly and you will need to > >> disable VAAI in ESXi. > >> > >> LIO does seem to implement VAAI properly, but performance is not nearly > >> as good as STGT even with VAAI's benefits. The assumption for the cause > >> is that LIO currently uses kernel rbd mapping and kernel rbd performance > >> is not as good as librbd. > >> > >> I recently did a simple test of creating an 80GB eager zeroed disk with > >> STGT (VAAI disabled, no rbd client cache) and LIO (VAAI enabled) and > >> found that STGT was actually slightly faster. > >> > >> I think we're all holding our breath waiting for LIO librbd support via > >> TCMU, which seems to be right around the corner. That solution will > > > > Is there a thread for that? Not a thread, but it has come up a few times... Maybe I'm getting ahead of myself. I can't wait for this solution to be available. > > > >> combine the performance benefits of librbd with the more feature-full > >> LIO iSCSI interface. The lrbd configuration tool for LIO from SUSE is > >> pretty cool and it makes configuring LIO easier than STGT. > >> > > > > I wrote a tcmu rbd driver a while back. It is based on gpl2 code, so > > Andy could not take it into tcmu. I attached it here if you want to play > > with it. > > > > Here it is attached in patch form built against the current tcmu code. > > I have not tested it since March, so if there have been major changes to > the tcmu code there might be issues. > > You should only use this for testing. I wrote it up in a night. I have > done very little testing. > > It only supports READ, WRITE, DISCARD/UNMAP, TUR, MODE_SENSE/SELECT, and > SYNC_CACHE. > Thanks for this! I was able to patch and compile without errors. I'm having trouble using it though. Does it require targetcli-fb? This should show up as a "User: rbd" backstore, right?
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