Re: 5% of blocks for root more than necessary?
17.10.2011 21:07, Lennart Sorensen wrote:
On Mon, Oct 17, 2011 at 09:03:15PM +0300, Vesa Paatero wrote:
When the Debian installer creates a file system, it reserves 5% of
blocks for root or privileged processes. That's an old default
percentage which could be replaced by a more appropriate amount.
Well it is the default of mkfs.ext[234]. I think if this should be
changed it would be by asking the maintainer of the mkfs tool for ext2/3/4
about it. Should Debian start overriding the filesystem maintainers
defauls in the installer if the user didn't explicitly request it?
I think the optimal amount of reservation is a distro-dependent
variable, for some part at least, that's why I'd not put the
responsibility on mkfs maintainers only.
Besides given what tends to happen to filesystem performance when you
pass about 90% full, having that 5% off limit to non root might actually
be a good thing. You don't want to be using that 5% anyhow.
On the other hand, when you are running short of disk space, the
priority shifts towards having as much space available as possible,
performance being secondary at that point.
I'd suggest that the reservation should be about the smallest size
that certainly suffices for the correct functioning of journaling and
all the necessary system processes you can expect in a Debian
system.
Educating users about the effects of full-stuffed disk on
performance or about the possibility to user the reserved space are
good things, too..
Reply to: