On Wednesday 17 of November 2010 18:38:29 Eric Sandeen wrote:
> On 11/17/10 8:49 AM, Åukasz OleÅ wrote:
> > Hi,
> >
> > I'm upgrading xfsprogs from 2.10.1 to the latest 3.1.4 version. I noticed
> > that when I'm creating large lvm volume (2T) the log size is almost 1G
> > in the old version it was 128M.
> > I know I can manipulate this value with -lsize option, but I'm wondering
> > why this difference is so huge?
> >
> > On this volume I have one sparse file which is exported by iSCSI Target.
> > I have script which calculates for me "seek" value for dd command and
> > now it returns me wrong values.
> > Can I stay with the old log size or maybe there are some good reasons to
> > use new values?
> >
> > Regards,
> > Åukasz OleÅ
>
> commit a6634fba3dec4a92f0a2c4e30c80b634c0576ad5
> Author: David Chinner <dgc@xxxxxxx>
> Date: Sun May 10 21:31:22 2009 +0200
>
> mkfs: allow to make larger logs
>
> Increase the maximum log size supported by mkfs.
>
> The log size can be increased easily in mkfs by changing a few
> defines and a couple of types to allow the log size to increase to
> just under 2GB. Theoretically, the log size can be made much, much
> larger than this (up to 2^32 sectors), but going beyond 2^31
> *bytes* causes integer overflow issues in the kernel log code.
>
> We use a maximum size of just under 2GB as exactly 2GB will cause
> overflow issues on the first transaction reservation.
>
> Maximum log size is now reached at a fs size of ~4TB.
>
> Signed-off-by: Dave Chinner <dgc@xxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>
>
> did:
>
> @@ -1737,10 +1737,10 @@ _("size %s specified for log subvolume is too
> large, maximum is %lld blocks\n"), logblocks = 0;
> } else if (loginternal && !logsize) {
> /*
> - * logblocks grows from min_logblocks to XFS_MAX_LOG_BLOCKS
> - * at 128GB
> - *
> - * 2048 = 128GB / MAX_LOG_BYTES
> + * With a 2GB max log size, default to maximum size
> + * at 4TB. This keeps the same ratio from the older
> + * max log size of 128M at 256GB fs size. IOWs,
> + * the ratio of fs size to log size is 2048:1.
> */
> logblocks = (dblocks << blocklog) / 2048;
> logblocks = logblocks >> blocklog;
>
> old MAX was:
>
> -#define XFS_MAX_LOG_BYTES (128 * 1024 * 1024)
>
> In your case ... I'm not sure a larger log is going to help, I think
> keeping it smaller is fine if you wish.
>
> Dave may have a different opinion though :)
>
> -Eric
Ok, so it's this commit http://git.kernel.org/?p=fs/xfs/xfsprogs-
dev.git;a=commitdiff;h=a6634fba3dec4a92f0a2c4e30c80b634c0576ad5
Would it be safe if I just revert this commit? It looks safe for me, but
maybe other things depends on it and I will break something.
Regards,
Åukasz OleÅ
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