Messages in this thread | | | From | Andi Kleen <> | Subject | Re: Btrfs: broken file system design | Date | Fri, 25 Jun 2010 11:15:55 +0200 |
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"Daniel Taylor" <Daniel.Taylor@wdc.com> writes: > > As long as no object smaller than the disk block size is ever > flushed to media, and all flushed objects are aligned to the disk > blocks, there should be no real performance hit from that.
The question is just how large such a block needs to be. Traditionally some RAID controllers (and possibly some SSDs now) needed very large blocks upto MBs.
> > Otherwise we end up with the damage for the ext[234] family, where > the file blocks can be aligned, but the 1K inode updates cause > the read-modify-write (RMW) cycles and and cost >10% performance > hit for creation/update of large numbers of files.
Fixing that doesn't require a new file system layout, just some effort to read/write inodes in batches of multiple of them. XFS did similar things for a long time, I believe there were some efforts for this for ext4 too.
-Andi -- ak@linux.intel.com -- Speaking for myself only.
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