Re: block chg tracking
- From: MARK BRINSMEAD <mark.brinsmead@xxxxxxxxx>
- To: Jeremy Schneider <jeremy.schneider@xxxxxxxxxxxxxx>
- Date: Mon, 16 Feb 2015 17:02:01 -0500
+1, at least so far as the "snapshot backups" are concerned. In my view,
you don't actually have a "backup" until the "snapshot" has been copied to
independent media.
As for "rm" providing a great compression ratio ... well, that's certainly
true. The *de-*compression performance really sucks, though. ;-) It kind
or reminds me of my (now ancient) university days, where the
circuitry-types used to joke about a new and infinitely fast
write-only-memory.
On Mon, Feb 16, 2015 at 12:43 PM, Jeremy Schneider <
jeremy.schneider@xxxxxxxxxxxxxx> wrote:
> FWIW, this is partly a terminology thing, but I get a little nervous
> when people talk about "snapshot-only backups". Snapshots are awesome
> - can be very useful as an intermediate step as you've pointed out,
> and can also provide quick & easy rollback points (similar to
> flashback database) for maintenance operations. But personally I
> think that it's _so_ crucial to have some kind of backup on different
> physical media from your primary. (Even the FRA can be on the same
> physical disks if you're not attentive to SAN config details!)
> Relying on snapshots alone for backups - even with the most
> bullet-proof SAN - is really dangerous...
>
> my 2c... and yeah, i know, ancient oft-beaten dead horse... but it
> probably never hurts to mention it once more!
>
> On Mon, Feb 16, 2015 at 10:16 AM, Mladen Gogala
> <dmarc-noreply@xxxxxxxxxxxxx> wrote:
> >
> > Every four to six hours? Full backup is usually run on daily basis. And
> even
> > every 4 to 6 hours is possible, if the backup is SAN snapshot.
> >
> > That's why a lot of attention needs to be devoted for
> > scheduling, unless the full backup is actually a snapshot.
> >
> > what Kenny described is not a typical solution. Kenny
> > described the snapshot-only solution which doesn't include long term data
> > preservation, like the one mandated by SOX or HIPAA. Those solutions can
> be
> > combined. Also, please note that snapshots are fast. Running a full DB
> > backup as snapshot every 4 to 6 hours is not a problem. Note that once
> you
> > have snapshot, copying the files to tape can be done using file system
> > utilities like tar, cpio or rm (if 100% compression is needed). The only
> > remaining problem is the one of cataloging these backups and modern
> backup
> > utilities do that for you.
>
> rm does indeed provide the best compression i've ever seen. i'd
> forgotten just how useful it is!
>
> --
> http://about.me/jeremy_schneider
> --
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>
>
>
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