SMSQL Near-Zero-Minute RPO - TR-3604 Procedure

[D_MACPHERSON2011]

Hi everyone,

I am looking to implement a near zero RPO for one of our clients. Looking through the TR-3604 document the recommended way to achieve this is the following:

“Scheduled full backups of the SQL Server database are replicated every four hours and the transaction log volume is replicated synchronously using SnapMirror.”

The document however doesn’t go into great detail regarding how this should be implemented, please could someone give me an over view if they have configured a DR site in this way before.

The way I see the configuration is:

User DB LUN – Async mirror to destination, SnapManager for SQL server completes full backups every 4 hours with update mirror option.

User LOGS LUN – Configured in Sync with destination.

The question I have are:

1. Can I have the 4 hourly full backup complete the transaction log backup at the same time and truncate the transaction log. Would this affect the sync LUN?
2. What would be the restore procedure in a DR scenario? Restore from Snap Manager/mount the USER LOGS LUN etc?

Any assistance would be greatly appreciated.

Regards,

Dave.

[radek_kubka]

Hi and welcome to the Community!

Personally, I would focus on how to actually fail-over SQL from site to site, rather than minimize RPO. It can be near-zero, but how about RTO?

There is no perfect answer for this, I am afraid. You can find what options I was thinking of here: http://communities.netapp.com/message/58927#58927. Unfortunately no one (so far) was keen to provide their point of view.

Regards,

Radek

[D_MACPHERSON2011]

Thanks for the reply and warm welcome Radek,

The overall RTO is gained from complete site failover including DNS redirect etc so isn’t governed by SQL server connectivity. I was  planning on completing ASYNC mirroring with hourly full SMSQL backups and 15 minute T-LOG backups giving me a 15 minute worst case RPO - however, the requirement of a 1minute RPO is now present causing me to look into SYNC T-Logs.

I believe I can restore to point in time by using the Full/T-Log backups, I was wondering how the 'live' transaction log (post backup) is replayed against the DB.

Thanks again,

Dave.

[radek_kubka]

I believe I can restore to point in time by using the Full/T-Log backups, I was wondering how the 'live' transaction log (post backup) is replayed against the DB.

it is a part of SMSQL workflow - you can either do a point-in-time restore, without an option to reply logs, or you can do a restore where the database stays in a recovery mode, ready for 'live' logs being replayed.