[pve-devel] qcow2 bench and speed optimisations

Alexandre DERUMIER aderumier at odiso.com
Fri Sep 14 09:49:37 CEST 2012


http://linux.die.net/man/8/ntfsclone

"
Sparse Files

A file is sparse if it has unallocated blocks (holes). The reported size of such files are always higher than the disk space consumed by them. The du command can tell the real disk space used by a sparse file. The holes are always read as zeros. All major Linux filesystem like, ext2, ext3, reiserfs, Reiser4, JFS and XFS, supports sparse files but for example the ISO 9600 CD-ROM filesystem doesn't.
"

----- Mail original ----- 

De: "Alexandre DERUMIER" <aderumier at odiso.com> 
À: "Dietmar Maurer" <dietmar at proxmox.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Vendredi 14 Septembre 2012 09:42:29 
Objet: Re: [pve-devel] qcow2 bench and speed optimisations 

xfs : ok 
http://en.wikipedia.org/wiki/XFS#Sparse_files 

ext4:ok 

ext3:ok 
ext2:ok 
http://superuser.com/questions/218395/about-file-size-and-disk-usage-in-ext3 

zfs: ok 


so, seem to be working on all main filesystems 


----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Vendredi 14 Septembre 2012 09:17:09 
Objet: RE: [pve-devel] qcow2 bench and speed optimisations 

> so raw and qcow2 with metadatas alloc are sparse files, but you need a 
> filesystem which support it. 

Do you know a filesystem which does not support sparse files? 
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