[pve-devel] create snapshots
aderumier at odiso.com
Fri Aug 31 13:38:06 CEST 2012
>>No, I meant a different issue. What if data is on the host/network cache? But I guess we
>>can assume that an fsync on the iscsi connection makes sure that all data is written?
-pause the vm
bdrv_flush_all, flush the datas (fsync), to it's waiting the datas are written to the stable storage.
(so that's datas are flushed from all the cache (guest + host) )
with novmstate + guest filesystem freeze with qemu-ga
xfs_freeze do the same thing (fsync + stop new write to filesystem)
----- 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 31 Août 2012 13:22:29
Objet: RE: [pve-devel] create snapshots
> >>I wonder it is would be safe to call an external script to create the snapshot
> >>Or is there still some data in the qemu block driver cache, or the host
> yes, I think taking snapshot don't flush datas.
> rbd devs said me that we need to freeze the filesystem with qemu-ga if we
> want to be sure that's all is fine.
> (Or filesystem will do a fsck at start to correct the missing data with his
> But if we save the state, that's not a problem, as the vm will save the
> missings data in the memory and will flush them when the vm will reload the
No, I meant a different issue. What if data is on the host/network cache? But I guess we
can assume that an fsync on the iscsi connection makes sure that all data is written?
Alexandre D e rumier
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