On Mon, 13 May 2002, at 9:28am, Steven Lembark wrote: > Depends on the size of a system. If you have too much ... of data there > is no effective way to back it up and restore it. In my experience, large systems are even more likely to require multiple levels of data redundancy. When you get into that space, though, you're not talking about running "tar" on the filesystem at 2 AM. :) Instead, you're talking application-level backups, storage-level snapshots, that sort of thing. Maybe the snapshots are dumped to tape, and the tapes kept offsite. Maybe they ship the whole storage array offsite. I've heard of or seen both. There are plenty of even more sophisticated solutions. > For a few tens of millions you can avoid tapes too :-) "Backup" does not have to mean "magnetic tape". The essential element is that the backup is offline, so that if the "live" system gets destroyed somehow, all is not lost. Yes, the downtime from such a disaster is extremely painful -- but not having the data at all is orders of magnitude more painful. > Banks ... use multiple centers with multiple computers with multiple EMC > systems with multiple volumes RAID-ed across multiple sets of duplicated > drives connected by multiple controllers across multiple lans and > heartbeat systems monitoring each of them. And offline backups kept in physically hardened offsite facilities on top of that. Banks sincerely believe they cannot have too many copies of their data. I've seen pictures of the offline and near-line facilities they use for this sort of thing -- warehouses full of shelves and shelves of data cartridges. > Archiving data to tape is a wonderful thing but won't help you if hardware > fails and you need quick access to the system. Offline backups are for disaster recovery, not availability. I think you're trying to say that, but the point is getting confused. The difference between a small office's and a large bank's disaster recovery plans is the difference between their definitions of "disaster". A small office probably considers a hard drive failure or OS corruption a "disaster". A bank thinks more along the lines of "multiple terrorist attacks". -- Ben Scott <bscott@ntisys.com> | The opinions expressed in this message are those of the author and do not | | necessarily represent the views or policy of any other person, entity or | | organization. All information is provided without warranty of any kind. | _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html