Re: Unable to restart Mon after reboot

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Tue, Jul 03, 2012 at 10:09:33AM -0700, Sage Weil wrote:
> The OSD keeps directories small on its own by breaking the contents of 
> large directories into smaller subdirectories.

Right, that's what I remembered.  At least for XFS that'll actually
give you much worse allocation patters as each new directory rotates
to a new allocation group.

> That said, on one system we did see what looked like crazy bad 
> fragmentation on an XFS directory... it had maybe 5 subdirs in it and many 
> many blocks.  That was probably shortly after it had been big and rehashed 
> its contents into the subdirs.  Yehuda probably remembers more.

Another reason why not doing the artifical directories is better...

> In any case, is there a way to prod XFS into defragging a specific 
> directory?

No.  XFS can only defragment regular files at the moment.

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