On Mon, Mar 28, 2011 at 2:06 PM, Eric Sandeen <sandeen@xxxxxxxxxx> wrote: > On 3/28/11 1:02 PM, Oren Elrad wrote: >> Undesired behavior; mke2fs defaults to reserving 5% of the volume for >> the root user. 5% of a 2TB volume is 100GB. The rationale for root >> reservation (syslogd, etc...) does not require 100GB. As volumes get >> larger, this default makes less and less sense. >> >> Proposal; If the user does not specify their preferred reserve_ratio >> on the command-line (-m), use the less of 5% or MAX_RSRV_SIZE. I >> propose 10GiB as a sensible maximum default reservation for root. >> >> Patch: Follows and http://capsid.brandeis.edu/~elrad/e2fsprog.gitdiff >> >> Tested on the latest git+patch, RHEL5 (2.6.18-194.17.1.el5) with a >> 12TB volume (which would reserve 600GB under the default!): > > There's been a bit of debate about this; is the space really saved > for root, or is it to stop the allocator from going off the rails > when the fs nears capacity? Both, really. > > I don't really have a horse in the race, but the complaint has certainly > come up before... it's just important to realize that the space isn't > only there for root's eventual use. > > No other fs that I know of enforces this "don't fill the fs to capacity" > common sense programatically, though. > > -Eric > [SNIP] Well, in my version you still get some reservation to prevent whatever woes (fragmentation, allocator slow-down) that accompany a nearly-full disk. If you think 25 or 50GiB is a more appropriate maximum default, I have no objections. Whatever the reason for reservation, more than 100GB is totally nonsensical IMHO. Oren Elrad Dept. of Physics Brandeis University -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
