On Fri, 2010-01-08 at 16:11 +1300, John Carter wrote: > Whilst wading through his blog [1] I came across his suggestion of "chattr > +A".
This is pretty cool and may well be what I've been after for some time. The single largest problem I've had with my computer is occassional periods of disk IO that cause all applications to grind to a halt. I tend to run a lot of applications and use up most of the RAM so it doesn't surprise me but it is very frustrating. I've already set my drives to noatime and I'm looking forward to seeing what difference that makes. > * You should mark things like /home with > chattr +T /home > > A directory with the 'T' attribute will be deemed to be the top > of > directory hierarchies for the purposes of the Orlov block > allocator. > This is a hint to the block allocator used by ext3 and ext4 that > the > subdirectories under this directory are not related, and thus should > be > spread apart for allocation purposes. For example it is a very > good > idea to set the 'T' attribute on the /home directory, so > that > /home/john and /home/mary are placed into separate block groups. > For > directories where this attribute is not set, the Orlov block > allocator > will try to group subdirectories closer together where possible. Am I right in assuming there is no harm in running chattr + T on an existing /home directory? The block allocator will start spreading the files into different block groups from that point onwards? Thanks for the great tip - hopefully this is going to make a big difference on my system.
