2GB memory limit running fsck on a +6TB device

Santi Saez santi at usansolo.net
Tue Jun 10 23:48:35 UTC 2008

Theodore Tso escribió:
> hmm.....  can you send me the output of dumpe2fs /dev/sdXX?  You can
> run that command while e2fsck is running, since it's read-only.  I'm
> curious exactly how big the filesystem is, and how many directories
> are in the first part of the filesystem.
Upsss... dumpe2fs takes about 3 minutes to complete and generates about 
133MB output file:

dumpe2fs 1.40.8 (13-Mar-2008)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          7701b70e-f776-417b-bf31-3693dba56f86
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal dir_index filetype sparse_super 
Default mount options:    (none)
Filesystem state:         clean with errors
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              792576000
Block count:              1585146848
Reserved block count:     0
Free blocks:              913341561
Free inodes:              678201512
First block:              0
Block size:               4096
Fragment size:            4096
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Mon Nov 13 10:12:49 2006
Last mount time:          Mon Jun  9 19:37:12 2008
Last write time:          Tue Jun 10 12:18:25 2008
Mount count:              37
Maximum mount count:      -1
Last checked:             Mon Nov 13 10:12:49 2006
Check interval:           0 (<none>)
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      afabe3f6-4405-44f4-934b-76c23945db7b
Journal backup:           inode blocks
Journal size:             32M

Some example output from group 0 to 5 is available at:


> How big is the filesystem(s) that you are backing up via BackupPC, in
> terms of size (megabytes) and files (number of inodes)?  And how many
> days of incremental backups are you keeping?  Also, how often do files
> change?  Can you give a rough estimate of how many files get modified
> per backup cycle?

Where are backing up several servers, near about 15 in this case, with 
60-80GB data size to backup in each server and +2-3 millon inodes, with 
15 day incrementals. I think near about 2-3% of the files changes each 
day, but I will ask for more info to the backup administrator.

I have found and old doc with some build info for this server, the 
partition was formated with:

    # mkfs.ext3 -b 4096 -j -m 0 -O dir_index /dev/sda4
    # tune2fs -c 0 -i 0 /dev/sda4
    # mount -o data=writeback,noatime,nodiratime,commit=60 /dev/sda4 /backup

I'm going to fetch more info about BackupPC and backup cycles, thanks Ted!!


Santi Saez

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