On 05/13/2010 01:56 AM, Willie Wong wrote:
On Thu, May 13, 2010 at 12:25:08AM +0200, Alex Schuster wrote:
The 5% is historical from days when disks are much smaller. If you
have a sensible partition scheme you only really need to reserve the
blocks on the $ROOT filesystem. If the partition in question (IIRC) is
only for /home, then you can just turn off the reserved blocks all
together.
Isn't another purpose of those 5% the reduction of fragmentation that
occurs more when there is few free space left? Although I also reduce ift
on very large partitions. But I never set it to exactly zero.
Perhaps? I don't know. My ext3 partitions with 0% are all for large
files (videos and music) that are more or less static, so I can't say
anything about fragmentation on them. My other partitions are all
reiser, so can't say anything about fragmentation on them either :)
The tune2fs man page mentions that fragmentation is also a reason:
-m reserved-blocks-percentage
Set the percentage of the filesystem which may only be allocated
by privileged processes. Reserving some number of filesystem
blocks for use by privileged processes is done to avoid
filesystem fragmentation, and to allow system daemons, such as
syslogd(8), to continue to function correctly after non-
privileged processes are prevented from writing to the
filesystem. Normally, the default percentage of reserved blocks
is 5%.
