VMware Tape Drive pass-through

If a tape drive comes up with VMW_SATP_ALUA rule in VMware vShpere (4.0 or later) you will most likely see input/output errors during backup operation on the VM you mapped to drive to. A working rule is VMW_SATP_LOCAL and you can change it using some simple steps.

  1. Find the module for SCSI/SAS HBA using esxcfg-scsidevs
    esx# esxcfg-scsidevs -a
    vmhba0 cciss link-n/a block.cciss/c0d0:0 (0:2:1.0) Compaq Computer Corporation Smart Array P400
    vmhba1 mptspi link-n/a pscsi.vmhba1 (0:7:1.0) LSI Logic / Symbios Logic ProLiant
    vmhba2 mptspi link-n/a pscsi.vmhba2 (0:7:1.1) LSI Logic / Symbios Logic ProLiant
  2. Add an additional rule for the HBA module the tape drive/changer is attached to
    esx# esxcli nmp satp addrule --satp VMW_SATP_LOCAL --driver="mptspi" --description="Tape drive support"
  3. Restart the ESX host to activate changes. The drive will now work as expected.
  4. Map the tape drive according to http://kb.vmware.com/kb/1016407

Note: As this issue is related to the HBAs and tape drvies/changers used not all environments are affected.

WWN Converter updated

I’ve just updated the little WWN Converter utility. Feel free and give it a shot. Feedback is appreciated. This tool is updated from time to time and you will receive updates automatically.

The tool provides you with the following:

  • Convert layout and/or transform WWNs,WWLIDs as well as MAC addresses
  • Print vendor information of indicated string
  • Log results to file, if required

You can download the current version via ClickOnce or in a ZIP file. Please keep in mind, that this piece of software is shippted without any warranty.

Changed from bblog to WordPress

As bblog was no longer actively maintained, I was forced to switch to something new. WordPress seems to be a good alternative. As it comes with some quite interesting features, you can expect to see something new here soon.

DM-MP and SVSP 3.02

Here is a working and well tested addition for your /etc/multipath.conf if you’re using RHEL4 and SVSP 3. Please keep in mind that RHEL4 does not have an ALUA hardware handler in kernel and requires the HP-EVA MS-DPM personality of the Linux host profile.

device {
  vendor                "HP"
  product               "HSVX700"
  path_grouping_policy  group_by_prio
  prio_callout          "/sbin/mpath_prio_hp_sw /dev/%n"
  hardware_handler      "0"
  path_checker          hp_sw
  failback              immediate
  no_path_retry         12
  rr_min_io             100

The modification will be available in RHEL4 Update 9 when available.

I expect the same settings to work for RHEL5-6 and SLES9-11, too. Newer Linux releases like RHEL5-6 and SLES10-11 support the ALUA hardware handler and should use the new ALUA personality which is available in SVSP 3.03 and later.

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