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How does DPM 2007 reserve space for Express Full backups / restore points? RRS feed

  • Question

  • Hi there,

    I am using DPM 2007 with SP1. I am wondering more or less how DPM assigns space for restore points and Express Full Backups. Logically I understand them to be similar, depending on the type of data I am backing up.

    Also, I understand that synchronizations are applied to the initial replica to make the first restore point. However, thereafter when the new synchronizations are scheduled to be committed to a restore point, does the new restore point replace the first replica? Or, is it added alongside the original replica? That being the case, it would theoretically use up the original data size, then the original data size again with the deltas, and so forth until the retention time is met? From what I've seen of the storage calculator, it should be the first case. Can anyone confirm this thinking?

    Thanks!

    • Edited by johnny mango Wednesday, July 21, 2010 3:45 PM typo
    Tuesday, July 20, 2010 12:29 AM

Answers

  • The basic concept as below (from http://www.microsoft.com/systemcenter/en/us/data-protection-manager/dpm-protect-exchange.aspx)

    DPM uses a combination of transaction log replication and block-level synchronization in conjunction with the Exchange Server VSS Writer to help ensure your ability to recover Exchange data. After the initial baseline copy of data, two parallel processes enable continuous data protection with integrity:

    1. Transaction logs are continuously synchronized to the DPM server, as often as every 15 minutes.

    2. An “express full” uses the Exchange Server VSS Writer to identify which blocks have changed in the entire production mail database, and sends just the updated blocks or fragments. This provides a complete and consistent image of the data files on the DPM server or appliance. DPM maintains up to 512 shadow copies of the Exchange Server database(s) by storing only the differences between any two images.

    So in my words ..... when you do an express full backup you will write the changes from the protected Exchange database to the copy on the DPM servers replica volume - as a result the overwritten blocks on the replica are essentially written to the recovery point volume. The replica copy will always be the same data as the data you are protecting.

    An incremental backup will only copy the changed log file block data across to the replica volume until an express full backup is completed.

    Hope this is helpful

    Sunday, July 25, 2010 10:26 PM