Good morning ALUGers. I have noticed something a little odd about the space allocation on my disks. Prompted by the disks getting rather full. Taking two in particular I see (using system monitor) device type total free available used /dev/sdb1 ext3 1386.0Gb 79.8Gb 10.0Gb 1306.2Gb 99% /dev/sdc1 ext3 1386.3Gb 111.0Gb 41.2Gb 1275.2Gb 96% Ok. total = free + used but why only 10Gb / 41.2Gb available? I find it hard to believe that there is 69.8Gb of disk lost by sector padding at the end of files or is allocated to the directory. Even more odd that both disks appear to have "lost" 69.8Gb. I get the same numbers (to 1Kb precision) if I use du and df to check the space. I don't know the ext3/4 file system layout and would like to know if these numbers are normal or exceptional. Could I have done something at mkfs time to "improve" on the above? BTW, Trash is empty. I'm not overly worried by this, it's just a "want to know" thing. The disk almost full problem will go away on the 3rd July when the automatic backup program deletes all the incremental backup data for June from these disks, which are my first line of system backups. I've had a very heavy month processing VHS tapes to mpeg4(xvid).avi files. -- nev
Morning Nev, On 24 June 2011 08:01, nev young <nev@nevilley.demon.co.uk> wrote:
Good morning ALUGers. ... I get the same numbers (to 1Kb precision) if I use du and df to check the space.
I get this; http://img193.imageshack.us/img193/5631/filesystems.png Is one of these measuring in kibi-bytes and the other kilo? -- James. http://www.jamesbensley.co.cc/
On 24/06/11 8:01 AM, nev young wrote:
I have noticed something a little odd about the space allocation on my disks. Prompted by the disks getting rather full.
Taking two in particular I see (using system monitor) device type total free available used /dev/sdb1 ext3 1386.0Gb 79.8Gb 10.0Gb 1306.2Gb 99% /dev/sdc1 ext3 1386.3Gb 111.0Gb 41.2Gb 1275.2Gb 96%
Ok. total = free + used but why only 10Gb / 41.2Gb available?
Hi Nev, I believe ext2/3 makes a percentage of the total space unavailable to unprivileged users, man tune2fs says: -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 filesys‐ tem fragmentation, and to allow system daemons, such as sys‐ logd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. Nor‐ mally, the default percentage of reserved blocks is 5%. Cheers, Rob. -- Robert Waldie | VP Business Development UK & Europe | Opengear robert.waldie@opengear.com | +44 (0)7766 866159 | http://opengear.com/uk Opengear Ltd. Herschel House, 58 Herschel St, Slough, Berkshire, England, SL1 1PG Registered in England, No. 07413660
On 24/06/11 10:08, Adam Bower wrote:
On Fri, Jun 24, 2011 at 09:31:07AM +0100, Robert Waldie wrote:
I believe ext2/3 makes a percentage of the total space unavailable to unprivileged users, man tune2fs says: ^^^^^ This. That fits, as it is 5% that has gone "missing". as these disks hold purely backup data I think I can safely reduce that 5%.
Thanks. -- nev Why can't the answer be obvious before I ask a dumb question?
On 24/06/11 13:46, nev young wrote:
^^^^^ This. That fits, as it is 5% that has gone "missing". as these disks hold purely backup data I think I can safely reduce that 5%.
Thanks.
5% seemed like a reasonable figure to allow root to do stuff when a disk is otherwise full back in the days before multi-terabyte file systems :)
participants (5)
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Adam Bower -
James Bensley -
nev young -
Robert Waldie -
Wayne Stallwood