On Fri, Feb 19, 2016 at 11:29:13AM -0500, Brian Foster wrote: > On Fri, Feb 19, 2016 at 05:16:28PM +0100, Jan Tulak wrote: > > On Fri, Feb 19, 2016 at 4:43 PM, Brian Foster <bfoster@xxxxxxxxxx> wrote: > > > On Fri, Feb 19, 2016 at 02:34:52PM +0100, Jan Tulak wrote: > > > > There is no check for a minimal value, so I can do -l su=1 (or su=0). Are > > > > there some caveats (other than performance) with such a small value? Can > > > > it be that we are missing a check? Because > > > > XLOG_BIG_RECORD_BSIZE > > > > and XLOG_MAX_RECORD_BSIZE are used and the upper bound is limited... > > > > > > > > > > On a quick test, it looks like mkfs just ignores certain log stripe unit > > > values that aren't block aligned. I'd probably expect this to behave > > > similar to the '-d su' option and complain about invalid input..? > > > > Sounds logical and like what I expected and didn't found. I will send a > > patch adding this check... the only question is, what should be the minimal > > value? Should I check it against block size and forbid smaller sizes? > > Aligning a stripe unit with length 1024 on 4096 blocks doesn't looks like a > > nice thing. :-) > > (And on a quick check, it seems that -d su is doing just that.) > > The man page says it must be a multiple of the fsb size. Indeed, '-d su' > complains about anything that is less than 1 FSB, so I would just go > with that. :) Keep in mind that a value of 0 in the superblock is completely acceptible, in which case the kernel treats the log stripe unit as being a single sector (i.e. same as a v1 log). See, for example, xlog_sync() where it works out the padding to use for the log buffer write. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
