2015-07-29 12:31 GMT+03:00 Liu Yuan <namei.u...@gmail.com>: > Technically, it won't affect the performance because index updates are not > range > but concrete in terms of underlying 4M block size. Only 2 or 3 indexes in a > range will be updated and 90+% updates will be only 1. So if 2 updates stride > a > large range, it will actually worse the performance of sheepdog because many > additional unref of object will be executed by sheep internally. > > It is not a performance problem but more the right fix. Even with your patch, > updates of inode can overlap. You just don't allow overlapped requests go to > sheepdog, which is a overkill approach. IMHO, we should only adjust to avoid > the overlapped inode updates, which can be done easily and incrementally on > top > of old code, rather than take on a complete new untested overkill mechanism. > So > what we get from your patch? Covering the problem and lock every requests? > > Your patch actually fix nothing but just cover the problem by slowing down the > request and even with your patch, the problem still exists because inode > updates > can overlap. Your commit log doesn't explain what is the real problem and why > your fix works. This is not your toy project that can commit whatever you > want. > >> BTW, sheepdog project was already forked, why don't you fork the block >> driver, too? > > What makes you think you own the block driver? > > We forked the sheepdog project because it is low quality of code partly and > mostly > some company tries to make it a private project. It is not as open source > friendly > as before and that is the main reason Kazutaka and I chose to fork the > sheepdog > project. But this doesn't mean we need to fork the QEMU project, it is an > open source project and not your home toy. > > Kazutaka and I are the biggest contributers of both sheepdog and QEMU sheepdog > block driver for years, so I think I am eligible to review the patch and > responsible to suggest the right fix. If you are pissed off when someone else > have other opinions, you can just fork the code and play with it at home or > you > follow the rule of open source project.
Jeff Cody, please be the judge, patch from Hitoshi solved my problem that i emailed in sheepdog list (i have test environment with 8 hosts on each 6 SSD disks and infiniband interconnect between hosts) before Hitoshi patch, massive writing to sheepdog storage breaks file system and corrupt it. After the patch i don't see issues. -- Vasiliy Tolstov, e-mail: v.tols...@selfip.ru
