Summary: EVA Continuous Access with TruCluster

From: Todd Acheson (acheson_at_ohio.edu)
Date: 05/24/05

  • Next message: Bjorn S. Nilsson: "RA3000 rebuild problems" 
    Date: Tue, 24 May 2005 11:27:01 -0400
To: tru64-unix-managers@ornl.gov

    The original question is at the end of this email.

    Continuous access does not provide seamless failover for a TruCluster. All
    worst case failures would require a reboot of the cluster.

    Suggestions for DR/HA included:

    - Use LSM for everything but CFS root, usr, var and boot partitions. Clone
    the cluster for quick recovery of the cluster upon EVA failure.

    - Script failover to remap the LUNS and reboot

    - Look at possible McData (or other vendor) switch options that might
    support some seamless failure. I haven't done this yet.

    - Performance of CA also has been raised as an issue, at least in
    synchronous mode. I don't know how to quantify this yet. Our physical
    separation of the EVAs would be only about 2km.

    Thanks to:

    Jeffrey Hummel
    Kelly Graham
    Tom Webster
    Raul Sossa
    Danielle Georgette
    Thomas Sjolshagen

    --On Wednesday, May 18, 2005 5:06 PM -0400 Todd Acheson <acheson@ohio.edu>
    wrote:

    > Hi,
    >
    > We had our EVA5K crash for unknown causes about 2 weeks ago and sustained
    > 24 hours of downtime. This raised the issue of how we could build more
    > redundancy into our storage stack.
    >
    > There is Continuous Access (CA), and as I understand it there would not
    > be seamless failover. You would mount the LUNs from the active EVA and
    > if that unit failed, you would have to manually remap all filesets to the
    > LUNs presented from the backup EVA.
    >
    > I was pointed to HP MetroClusters as a way to seamlessly have EVA
    > failover, but in looking at the HP website, Metroclusters only appear to
    > work with HP-UX. Can anyone validate this??
    >
    > If CA is indeed only a manual failover for TruClusters then perhaps I
    > should just go back to LSM and use it to maintain consistency between 2
    > EVAs. I used to use LSM prior to TruClusters but am a little concerned
    > because we have on the order of 20 ADVFS domains with some that are very
    > busy. Not sure if LSM would introduce any performance penalties.
    >
    > Todd Acheson
    > Ohio University
    >

  • Next message: Bjorn S. Nilsson: "RA3000 rebuild problems"

    Relevant Pages

    • EVA Continuous Access with TruCluster
      ... presented from the backup EVA. ... I was pointed to HP MetroClusters as a way to seamlessly have EVA failover, ... If CA is indeed only a manual failover for TruClusters then perhaps I ... I used to use LSM prior to TruClusters but am a little concerned ...
      (Tru64-UNIX-Managers)
    • Re: Best way to simulate a failure
      ... failure of a single box running Solaris. ... Nothing so drastic as pulling drives, network cables or else. ... How would you compare the risk of using STOP-A to ... I want a realistic failover test ...
      (comp.sys.sun.hardware)
    • Re: Best way to simulate a failure
      ... failure of a single box running Solaris. ... each involving different hardware generations. ... Nothing so drastic as pulling drives, network cables or else. ... the failover has worked and another node ...
      (comp.sys.sun.hardware)
    • Re: dual homing a freebsd server
      ... primary network dies I want it to failover to the other card on the fly. ... depending on how long-lived the critical ... Note that the failure will ...
      (freebsd-questions)
    • Quantcast