VMware vSphere

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  • 1.  virtual harddrives on datastores

    Posted Nov 28, 2017 06:51 PM

    Hello,

    point me at the documentation if this has already been answered.

    I have a virtual database server with 6 virtual harddisks.

    I have 6 1TB VMWare iSCSI datastores attached to the ESXi server from the SAN.

    All things being equal, is it better to:

    put the whole server (6 drives) on 1 datastore,

    or spread the drives out over over all the datastores?

    Thank You.



  • 2.  RE: virtual harddrives on datastores

    Posted Nov 28, 2017 08:51 PM

    It depends on the implementation behind the iSCSI LUNs.  Are they all coming off the same array?  Are they coming off the same physical disk group/volume?

    If on the back-end they're basically sharing the same disk hardware, then it's probably 6 in one and half-dozen in the other.    I would possibly lean toward one big disk just to avoid size limitation issues on the guest OS, but it probably doesn't matter.

    If the LUNs are on different physical disks with different characteristics, then it may be better to keep them separate.

    With databases you need to worry about the read/write profile and match the disks to those characteristics, so usually you split it up that way and put different parts of the database on different LUNs with characteristics to match those parts' needs.