Check into synthetic fulls…especially optimized synthetic
fulls….that way you are only really doing a differential every night and
letting NBU handle the creation of the full…this should dramatically shrink
the time it takes to do the backups.
From:
veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of JC
Cheney
Sent: Friday, July 16, 2010 5:09 AM
To: Dean; veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] How to implement a 24 hour RPO with a
traditionalbackup system.
Snapshot client? I guess you’d still be 24hrs + time to
take the snap but that should be negligible…
From:
veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Dean
Sent: 16 July 2010 05:54
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] How to implement a 24 hour RPO with a
traditionalbackup system.
Hi folks,
This is in no way NetBackup specific, but I'm wondering if some of the smart
people on this mailing list might have some thoughts.
The company I work for have several service classes for Disaster
Recoverability, mainly based on RPO (Recovery Point Objective). RPO refers to
the amount of data loss that the company are willing to sacrifice in the case
of a disaster. The customer is charged higher rates for the higher service
classes.
Platinum level service class means zero data loss, so that basically means
synchronous cross-site disk mirroring for the applications.
Gold level is 2 hours, so we use asynchronous disk mirroring, and/or ship the
archive logs to the other site every 30 minutes or so.
Silver is 24 hours. The large majority of our backup clients fall into this
category. Silver class is all based on tape backup/recovery. It's the
traditional overnight backup to tape (or disk, VTL, whatever).... fulls on the
weekend, incrementals on weeknights.
But one of our clients has questioned this worst-case 24 hour RPO, and their
query is quite valid.
Here is an example:
There is a system with 24 hour RPO that we backup every night at 6PM. The
backup takes one hour. So, if a disaster occurs at 6:59 PM, before tonight's
backup completes, we have to restore from the previous night's backup. But,
really, that backup is only consistent as of 6PM the previous night, when the
backup *started*. That means our worst case RPO is actually 25 hours.
I know this can be fixed with disk mirroring, but I'm looking for ways around
this using purely "traditional" tape based (or disk) backup. If we're
going to mirror all these systems, we'd be effectively moving them all to the
Platinum DR class, and the customer is not willing to pay for that.
To do it with a traditional daily backup regime, we'd have to ensure that each
day's backup completed less than 24 hours before the previous day's backup
started, which means the backup window would constantly rotate throughout the
day. Obviously that's not realistic.
The easy solution is to adjust the SLA to say that the RPO is "24 hours,
plus the elapsed time of your backup", but the customer will not accept
that.
We could also do something like running two backups a day, but obviously that
will double the resources we need for our backup infrastructure, and I don't
think the customer would be happy with all their servers grinding to a halt
when the backups kick off in the middle of the day.
Has anyone else worked through this issue?
Any input appreciated :)
Thanks,
Dean