Re: [PATCH] Clustering indirect blocks in Ext3 (was Ext2)

[Eric Sandeen <sandeen@redhat.com>]

Eric Sandeen wrote:
> Abhishek Rai wrote:
>> This patch modifies the block allocation strategy in ext3 in order to
>> improve fsck performance. This was initially sent out as a patch for
>> ext2, but given the lack of ongoing development on ext2, I have
>> crossported it to ext3 instead. Slow fsck is not a serious problem on
>> ext3 due to journaling, but once in a while users do need to run full
>> fsck on their ext3 file systems. This can be due to several reasons:
>> (1) bad disk, bad crash, etc, (2) bug in jbd/ext3, and (3) every few
>> reboots, it's good to run fsck anyway. This patch will help reduce
>> full fsck time for ext3. I've seen 50-65% reduction in fsck time when
>> using this patch on a near-full file system. With some fsck
>> optimizations, this figure becomes 80%.
> 
> For what it's worth, this speeds large file removals, too:
> 
> http://people.redhat.com/esandeen/rm_test/ext3_metacluster_rm.png
> http://people.redhat.com/esandeen/rm_test/ext3_rm.png

Or, for more direct comparison:

http://people.redhat.com/esandeen/rm_test/ext3_rm_stock_vs_metacluster.png

-Eric