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File size differences



Hey,

I have two identical machines setup with a RAID 5 array. One of them is used for
failovers and data from the master is synced everyday using rsync to the
failover machine. The data on this disks are usually intranet KB's, DB's etc..

The RAID 5 arrays are formatted using the default options i,e mkfs.ext3
/dev/Xda. The RAID controller is 3ware escalade and each disk member in the RAID
5 array are 400Gb IDE.

Now the wierd part is, after syncing the failover with the master and comparing
the size of each dir and file I find some files where the size mismatches..

[root storage-master repositories]# du --si
"/store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt"
8.2k    /store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt

root storage-slave compare]# du --si
"/store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt"
4.1k    /store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt

stat on the same file shows..

[root storage-master repositories]# stat
"/store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt"
  File: `/store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt'
  Size: 1126            Blocks: 16         IO Block: 4096   regular file
Device: 801h/2049d      Inode: 10403842    Links: 1
Access: (0775/-rwxrwxr-x)  Uid: (   48/  apache)   Gid: (   48/  apache)
Access: 2006-09-11 12:22:24.000000000 +0530
Modify: 2004-09-23 16:45:31.000000000 +0530
Change: 2006-02-23 18:31:42.000000000 +0530

root storage-slave compare]# stat "/store1/SystemAdministration-OldVideos/SysAd
Training/Technology Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt"
  File: `/store1/SystemAdministration-OldVideos/SysAd Training/Technology
Basics/000_READ_ME_FIRST_FOR_INDEX_OF_VIDEOS.txt'
  Size: 1126            Blocks: 8          IO Block: 4096   regular file
Device: 801h/2049d      Inode: 23019536    Links: 1
Access: (0775/-rwxrwxr-x)  Uid: (   48/  apache)   Gid: (   48/  apache)
Access: 2001-01-28 21:10:14.000000000 +0530
Modify: 2004-09-23 16:45:31.000000000 +0530
Change: 2001-01-28 21:10:14.000000000 +0530

The number of blocks allocated on the master seems to be 16 and the failover is
8. Is this the reason for the file size difference even though the content is
the same ?

I rsynced the same file from the master to a different server and the file size
matched. Any reason why the no. of blocks allocated is different across both
this machines ?

The file i gave above is just a example and there are many more files like this.
 Also only 10% of the files have different sizes. I.e out of 263032
files/folders only 17655 have the above problem.

Below is the ext3 filesystem info on both the master and failover.

[root storage-master repositories]#  dumpe2fs -h /dev/sda1
dumpe2fs 1.35 (28-Feb-2004)
Filesystem volume name:   /store1
Last mounted on:          <not available>
Filesystem UUID:          2368a03d-f21f-4c5e-b12a-cbd2c726237c
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode filetype
needs_recovery sparse_super large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              97681408
Block count:              195354408
Reserved block count:     9767720
Free blocks:              22200635
Free inodes:              97329015
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1024
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Tue Jun 28 17:06:41 2005
Last mount time:          Tue Oct 10 20:22:02 2006
Last write time:          Tue Oct 10 20:22:02 2006
Mount count:              93
Maximum mount count:      -1
Last checked:             Thu Oct 20 19:03:56 2005
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
First orphan inode:       52691033
Default directory hash:   tea
Directory Hash Seed:      0449f257-e47d-4faf-92fa-fa497efab3a1
Journal backup:           inode blocks

[root storage-slave compare]# dumpe2fs -h /dev/sda1
dumpe2fs 1.35 (28-Feb-2004)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          b003440d-d153-4cec-a668-94f5482d54cf
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode filetype
needs_recovery sparse_super large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              97681408
Block count:              195354408
Reserved block count:     9767720
Free blocks:              26532722
Free inodes:              97327187
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1024
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Tue Jun 28 14:37:12 2005
Last mount time:          Thu Nov 16 01:11:30 2006
Last write time:          Thu Nov 16 01:11:30 2006
Mount count:              65
Maximum mount count:      -1
Last checked:             Thu Oct  6 15:11:41 2005
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:      fa6b4317-d51d-4050-b0f3-c72b45148777
Journal backup:           inode blocks

tia
dushy






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