support quality (Re: dump | restore fails: unknown tape headertype 1853384566)

[Peter C. Lai]

On 2009-03-26 02:45:45PM +0000, Jake Scott wrote:
> Absolutely.  You really must use a tool that interacts with the database to 
> perform the backup.  Most commercial DBs have hooks that allow the backup 
> routines to call out to custom snapshot facilities.  One would usually 
> request a backup through the database, which would then freeze IO to its 
> data files and maybe log files, deal with flushing caches etc and then call 
> your snapshot routine.  I'm not aware that MySQL and Postgres do though so 
> the best you can do is a dump.

With MySQL at least, you can (ab)use the replication facilities so that
you can set up a "slave" and do the fs-level dump while the slave is in a
"frozen" state - the last time I played with MySQL, you could basically
desync your slave for a period of time (basically until transaction logs
are purged on the master), during which the slave will be consistent; do
the fs-level backup then kick the master to sync with the slave again.

-- 
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Peter C. Lai                 | Bard College at Simon's Rock
Systems Administrator        | 84 Alford Rd.
Information Technology Svcs. | Gt. Barrington, MA 01230 USA
peter AT simons-rock.edu     | (413) 528-7428
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