Re: Can we trust fsync?

Craig Ringer <craig(at)2ndquadrant(dot)com> writes:
> The amount of change in write reliablity behaviour in Linux across
> kernel versions, file systems and storage abstraction layers is worrying
> - different results for LVM vs !LVM, md vs !md, ext3 vs other, etc.

Well, we pretty much *have to* trust fsync --- there's not a lot we can
do if the kernel doesn't get this right. My takeaway is that you don't
want to be running a production database on bleeding-edge kernels or
filesystem stacks. If you want to use Linux, use a distro from a vendor
with a track record for caring about stability. (I'll omit the commercial
for my former employers, but ...)

Also, it's not that hard to do plug-pull testing to verify that your
system is telling the truth about fsync. This really ought to be part
of acceptance testing for any new DB server.

regards, tom lane