sparsify - utility to punch out blocks of 0s in a file
Raghavendra D Prabhu
raghu.prabhu13 at gmail.com
Sun Feb 5 09:05:44 CST 2012
Hi,
* On Sat, Feb 04, 2012 at 02:10:30PM -0600, Eric Sandeen <sandeen at redhat.com> wrote:
>On 2/4/12 2:04 PM, Eric Sandeen wrote:
>> Now that ext4, xfs, & ocfs2 can support punch hole, a tool to
>> "re-sparsify" a file by punching out ranges of 0s might be in order.
>
>Gah, of course I sent the version with the actual hole punch commented out ;)
>Try this one.
>
>[root at inode sparsify]# ./sparsify -v fsfile
>blocksize is 4096
>orig start/end 0/536870912/0
>new start/end/min 0/536870912/4096
>punching out holes of minimum size 4096 in range 0-536870912
>punching at 16384 len 16384
>punching at 49152 len 134168576
>punching at 134234112 len 134201344
>punching at 268455936 len 134197248
>punching at 402669568 len 134201344
>[root at inode sparsify]#
>
>Hm but something is weird, right after the punch-out xfs says
>it uses 84K:
>
>[root at inode sparsify]# du -hc fsfile
>84K fsfile
>84K total
>
>but then after an xfs_repair it looks saner:
># du -hc fsfile
>4.8M fsfile
>4.8M total
>
>something to look into I guess... weird.
>
>
>
>
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>xfs at oss.sgi.com
>http://oss.sgi.com/mailman/listinfo/xfs
So I tried with both resparsify and with cp --sparse, the results
before xfs_repair looks different (5 extents vs 1) but after that
it looks similar (5 extents vs 4)
Regards,
--
Raghavendra Prabhu
GPG Id : 0xD72BE977
Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977
www: wnohang.net
-------------- next part --------------
>>dd if=/dev/zero of=tst bs=1M count=100 (/tmp)~20:08-0
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 0.0722117 s, 1.5 GB/s
>>mkfs.xfs tst (/tmp)~20:08-0
meta-data=tst isize=256 agcount=4, agsize=6400 blks
= sectsz=512 attr=2, projid32bit=0
data = bsize=4096 blocks=25600, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal log bsize=4096 blocks=1200, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
>>filefrag -v tst (/tmp)~20:08-0
Filesystem type is: ef53
File size of tst is 104857600 (25600 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 913408 2048
1 2048 1030144 915456 2048
2 4096 1024000 1032192 2048
3 6144 970752 1026048 2048
4 8192 1026048 972800 2048
5 10240 1196032 1028096 2048
6 12288 974848 1198080 2048
7 14336 1210368 976896 4096
8 18432 972800 1214464 2048
9 20480 1214464 974848 4096
10 24576 915456 1218560 1024 eof
tst: 11 extents found
>>=du -hc tst (/tmp)~20:08-0
101M tst
101M total
>>cp --sparse=always tst tst1 (/tmp)~20:08-0
>>=du -hc tst (/tmp)~20:08-0
101M tst
101M total
>>=du -hc tst* (/tmp)~20:08-0
101M tst
160K tst1
101M total
>>filefrag -v tst1 (/tmp)~20:08-0
Filesystem type is: ef53
File size of tst1 is 104857600 (25600 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 0 16 unknown,delalloc
tst1: 1 extent found
>>./resparsify tst (/tmp)~20:09-0
punching out holes of minimum size 4096 in range 0-104857600
>>=du -hc tst* (/tmp)~20:09-0
88K tst
160K tst1
248K total
>>filefrag -v tst (/tmp)~20:09-0
Filesystem type is: ef53
File size of tst is 104857600 (25600 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 913408 4
1 8 913416 913412 4
2 6400 971008 913420 4
3 12800 975360 971012 5
4 19200 973568 975365 4
tst: 5 extents found>>xfs_repair tst (/tmp)~20:17-0
Phase 1 - find and verify superblock...
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan and clear agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
Phase 5 - rebuild AG headers and trees...
- reset superblock...
Phase 6 - check inode connectivity...
- resetting contents of realtime bitmap and summary inodes
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify and correct link counts...
done
>>=du -hc tst (/tmp)~20:19-0
4.8M tst
4.8M total
>>filefrag -v tst (/tmp)~20:19-0
Filesystem type is: ef53
File size of tst is 104857600 (25600 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 913408 4
1 8 913416 913412 4
2 6400 971008 913420 4
3 12800 975360 971012 1204
4 19200 973568 976564 4
tst: 5 extents found
>>xfs_repair tst1 (/tmp)~20:20-0
Phase 1 - find and verify superblock...
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan and clear agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 3
- agno = 2
- agno = 1
Phase 5 - rebuild AG headers and trees...
- reset superblock...
Phase 6 - check inode connectivity...
- resetting contents of realtime bitmap and summary inodes
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify and correct link counts...
done
>>=du -hc tst1 (/tmp)~20:23-0
4.9M tst1
4.9M total
>>filefrag -v tst1 (/tmp)~20:23-0
Filesystem type is: ef53
File size of tst1 is 104857600 (25600 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 1218560 16
1 6400 1231104 1218576 8
2 12800 1237504 1231112 1204
3 19200 1239808 1238708 8
tst1: 4 extents found
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