Re: [Moosefs-users] Creating sparse file

[Michał B. <mic...@ge...>]

Hi Jakub!

Sparse files work a little bit differently on MooseFS and are not properly reported by 'du' command. You don't need to bother about this - it is how it works here.


Kind regards
Michał Borychowski 
MooseFS Support Manager
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Gemius S.A.
ul. Wołoska 7, 02-672 Warszawa
Budynek MARS, klatka D
Tel.: +4822 874-41-00
Fax : +4822 874-41-01


-----Original Message-----
From: Jakub Mroziński [mailto:ja...@31...] 
Sent: Friday, January 06, 2012 1:10 PM
To: moo...@li...
Subject: [Moosefs-users] Creating sparse file

Hello,
Im trying to create sparse files on mfs but it isn't working.

On MFS:
local:/mfs# dd if=/dev/zero of=jakub.test bs=4096 count=0 seek=1000 0 bytes (0 B) copied, 0.000205242 s, 0.0 kB/s local:/mfs# du -h jakub.test
4.0M    jakub.test

On local disk:
local:~# dd if=/dev/zero of=jakub.test bs=4096 count=0 seek=1000 0 bytes (0 B) copied, 1.0481e-05 s, 0.0 kB/s local:~# du -h jakub.test
0       jakub.test

As you can see on my local hdd everything is fine, file size is 0. On MFS file size is 4Mb.

What about cp?
local:~# cp --sparse=always jakub.test /mfs/ local:/mfs# du -h /mfs/jakub.test
4.0M    jakub.test

local:/mfs# cp --sparse=always jakub.test /root/jakub.test2 local:~# du -h /root/jakub.test2
0       jakub.test2

After cp from MFS to local hdd sparse file has good size.

What im doing wrong? Why all sparse files sizes on MFS are >0?
 
--
Jakub Mroziński




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