Kris Kennaway wrote:
It's possible you're seeing deadlock bugs in the snapshot code; you'd need to compile your system with DDB support and obtain traceback information as described in the developers' handbook chapter on kernel debugging.
Ok. As soon as I get the chance, I'll do this (I cannot stop a whole network right away).
The snapshot code was intended to support background fsck and that alone. It's also optionally used by the dump code, but it was not written as a general-purpose live filesystem snapshot service.
Ok.
I just think that this, as well as the disclaimer about it being alpha code and the access locks, should be mentioned in the Handbook. Reading that chapter or mksnap_ffs's manual, I didn't get it and I suspect people might get the idea that it is stable code, which provides some functionality that it doesn't.
Are there other alternatives for live backups?
Plenty, if you don't demand an instantaneous image of the backup image.
That depends on what you mean for instantaneous...
I'll explain my needs briefly: I export (via Samba) a whole bunch of databases that 9 clients read and write. I do not have more details (I didn't write that app myself).
The needs are:
a) backup data so that in case of severe failure we can get it rapidly back (we are going to loose the last transactions, obviously);
b) replicate everything to another machine (via rsync) so that a remote user can see a snapshot of the system status.
We probably can live with some incoherent records in a) (after all, something will almost for sure need manual fix anyway); as for b) I fear it might be more prone to problems.
So, if for instantaneous you mean at a specific time, I don't care at all wether the image is made an hour earlier or later. All I'd like is coherence.
BTW, we have almost no room for changes on the client side :(
The pros and cons of the snapshot code have been discussed on the mailing lists, and there is a (slightly outdated) information file here: /usr/src/sys/ufs/ffs/README.snapshot
I'm reading all this stuff; I might get back with some more questions later :)
bye & Thanks av. _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
