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allways inconsistent or syncronizing RRS feed

  • Question

  • I'm testing DPM prior to rollout and I'm having some consistent problems.
    The DPM server is 2008R2 fully patched and updated with Dual Xeon E5620
    2.4GHz with 12GB RAM. Backup is "Short Term" to an iSCSI disk with 5TB of
    space.
    There are only 2 agent servers currently, both are 2008R2. One is a VM
    running MS SQL, file and print. The other is the Host for the VM which is
    running a second VM (not currently connected to DPM), File and print.
     
    When I first set up protection it takes days (2 to 4) for the initial sync
    to complete, with repeated inconsistency errors and manual resyncs with
    consistency checks. And even though I have the volumes set to automatically
    expand I end up having to expand them manually.
     
    After a week of running, the host protected machine still shows
    synchronizing for the BMR and system state.
     
    I've run the system with more protected machines and it's pretty much the
    same, VERY slow to sync if it ever does and repeated errors resulting in
    inconsistencies.
     
    Help!
    RC
     
     
    Monday, April 2, 2012 2:54 PM

All replies

  • Hello,

    The process:

    1.) SQL scheduler kicks off the DPM service to start the job.
    2.) DPM wakes up DPMRA on the DPM server to start communicating with the target server.
    3.) DPM DPMRA talks to the target server to take a snapshot.  It wakes up the target Server DPMRA.
    4.) The target server DPMRA sees the datasource and tells the server to leverage WSB. 
    5.) WSB takes the backup and transfers it to the local DPMRA.
    6.) The local DPMRA then transfers the data to the DPM server which writes it directly to the storage pool. 

    If there is any weak link in this process the backup may be slow or even fail.  This is just the general architecture, this does not even scratch the surface of other components that comes into play.

    Questions:
    1.) Is this DPM version 7707 or is it earlier? (click the "i" in the right hand corner)

    2.) What is the link of between the DPM and target server? 512Kbps? 1 gig link?
    Distance? (same location? different state?)

    3.) On the HyperV host where are the guest VHD residing? If on the C drive and the C drive is listed as a critical volume then we will include the VHD's in the BMR and it can take quite a while in addition to consuming a lot of space in the storage pool.

    4.) What's the page file size for the DPM server?
    http://technet.microsoft.com/en-us/library/ff399244.aspx : “DPM requires a pagefile size that is 0.2 percent the size of all recovery point volumes combined, in addition to the recommended size (generally, 1.5 times the amount of RAM on the computer). For example, if the recovery point volumes on a DPM server total 3 TB, you should increase the pagefile size by 6 GB.”

    Leaving the page file for DPM to "system managed" usually is not enough.

    5.) If you toggle off chimney and\or RSS on the DPM server, does it make a difference?
    Chimney
    To enable chimney:   netsh int tcp set global chimney=enabled
    To disable chimney:   netsh int tcp set global chimney=disabled

    RSS
    To enable RSS:    netsh int tcp set global rss=enabled
    To disable RSS:     netsh int tcp set global rss=disabled
    To determine the current status of RSS, follow these steps:    netsh int tcp show global

    951037 Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008: http://support.microsoft.com/default.aspx?scid=kb;EN-US;951037


    These are all good places to start.



    Regards, Shane. Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. This posting is provided "AS IS" with no warranties, and confers no rights.


    • Edited by ShaneB. _ Friday, April 6, 2012 7:54 PM
    Friday, April 6, 2012 7:51 PM