[Ocfs2-users] Large difference between space used on reiserfs vs ocfs2

[Sunil Mushran]

So that is 32K clustersize. Meaning each file will consume
atleast that much space. While a large clustersize is useful
when dealing with large files (read datafiles), it will almost
always lead to space wastage when dealing with a general
purpose fs.

It could be that you did not choose this value and that mkfs
chose it for you. Older mkfs releases chose higher defaults.
With 1.2.7, we've changed the heuristics to choose the smallest
cs that can address the volume. Meaning 4k.

Luis Freitas correctly pointed out that it could be because
ocfs2 uses large inodes. And that that will also lead to more
space usage as compared to reiser. To solve this, we've recently
added inline data in 2.6.24. Inline data allows us to pack file
data into the inode itself. This will be very useful for fs' having
lots of small files. It will be available in ocfs2 1.4.

Sunil

Michael M. wrote:
>         Revision: 0.90
>         Mount Count: 0   Max Mount Count: 20
>         State: 0   Errors: 0
>         Check Interval: 0   Last Check: Fri Feb 23 02:43:43 2007
>         Creator OS: 0
>         Feature Compat: 0 None
>         Feature Incompat: 0 None
>         Feature RO compat: 0 None
>         Root Blknum: 17   System Dir Blknum: 18
>         First Cluster Group Blknum: 8
>         Block Size Bits: 12   Cluster Size Bits: 15
>         Max Node Slots: 10
>         Label: www
>         UUID: 0F98901B58E64D57B8A5556E8DC6DDC1
>         Inode: 2   Mode: 00   Generation: 2374663631 (0x8d8a7dcf)
>         FS Generation: 2374663631 (0x8d8a7dcf)
>         Type: Unknown   Attr: 0x0   Flags: Valid System Superblock
>         User: 0 (root)   Group: 0 (root)   Size: 0
>         Links: 0   Clusters: 6866783
>         ctime: 0x45dec55f -- Fri Feb 23 02:43:43 2007
>         atime: 0x0 -- Wed Dec 31 16:00:00 1969
>         mtime: 0x45dec55f -- Fri Feb 23 02:43:43 2007
>         dtime: 0x0 -- Wed Dec 31 16:00:00 1969
>         ctime_nsec: 0x00000000 -- 0
>         atime_nsec: 0x00000000 -- 0
>         mtime_nsec: 0x00000000 -- 0
>         Last Extblk: 0
>         Sub Alloc Slot: Global   Sub Alloc Bit: 65535
>
>
> -----Original Message-----
> From: Sunil Mushran [mailto:Sunil.Mushran at oracle.com] 
> Sent: Wednesday, December 26, 2007 10:57 AM
> To: Michael M.
> Cc: ocfs2-users at oss.oracle.com
> Subject: Re: [Ocfs2-users] Large difference between space used on reiserfs
> vs ocfs2
>
> What's your blocksize/clustersize?
>
> If you are on 1.2.7 tools, do:
> $ tunefs.ocfs2 -q -Q "bs=%B\ncs=%T\n" /dev/sdX
>
> If not, do:
> $ debugfs.ocfs2 -R "stats" /dev/sdX
>
> Michael M. wrote:
>   
>> Dear list,
>>
>>  
>>
>> I have all of my web files for my apache servers on multiple machines 
>> placed on ocfs2 volumes. I recently did an rsync to a reiserfs volume 
>> on an external usb harddrive, and df reports the following:
>>
>>  
>>
>> (ocfs2 is on top, reiserfs on bottom)
>>
>>  
>>
>> /dev/sde5            218757056 176814592  41942464  81% /mnt/www
>>
>> /dev/sdd1            732549604 117493932 615055672  17% /mnt/pba-web
>>
>>  
>>
>> Is this normal?
>>
>>  
>>
>> Thanks,
>>
>> Michael
>>
>> ------------------------------------------------------------------------
>>
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>>     
>
>
>