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9 replies Latest Post - ‏2013-07-20T06:30:46Z by Ernesto Sanchez
SystemAdmin
SystemAdmin
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Pinned topic How to configure RAID on a P710 where VIOS / IVM is going to be installed?

‏2013-02-15T04:12:57Z |
HI,

I have a new P710 server with three 300GB internal disks. It is required to configure RAID 1 and installed VIOS using HMC OR IVM directly.

Can someone help me in terms of required steps to do in configuring RAID 1 and installing VIOS or IVM?

Step-by-step instructions OR a URL containing above information is highly aprreciated.
Thank you in advanced.
Updated on 2013-02-21T20:42:23Z at 2013-02-21T20:42:23Z by dukessd
  • dukessd
    dukessd
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    Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

    ‏2013-02-16T00:23:00Z  in response to SystemAdmin
    http://www-01.ibm.com/support/docview.wss?uid=isg3T1010980
    • SystemAdmin
      SystemAdmin
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      Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

      ‏2013-02-19T00:29:46Z  in response to dukessd
      pardon me, I am still new to power systems...

      I want to know whether it is possible to configure hardware RAID for the local SAS disks attached, preferably RAID 1, and install VIOS on top of those RAID array? (similar to configure RAID on a X series server and install ESX or Linux etc. on top of the RAID array)
      So that single disk failure won't be an issue.
      • dukessd
        dukessd
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        Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

        ‏2013-02-19T01:07:27Z  in response to SystemAdmin
        Well that would depend on whether you have a hardware RAID adapter for your drives.

        What type of adapter are they connected to?

        If they are not connected to a hardware RAID adapter then you cannot use hardware RAID but you can still use the link above to configure LVM mirroring.

        HTH
        • SystemAdmin
          SystemAdmin
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          Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

          ‏2013-02-19T04:01:13Z  in response to dukessd
          In the server there is a Storage Backplane -- 3 SFF Drives/SATA DVD/ HH Tape (EJ0E), and it has three 300GB 15K RPM SAS SFF disk drives.

          So can I do hardware based RAID config?
          • dukessd
            dukessd
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            Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

            ‏2013-02-20T01:26:17Z  in response to SystemAdmin
            I don't see where in your last post it says you have a RAID adapter or RAID enablement feature for your disk backplane so I guess the answer is no.

            If it's a new system then call IBM support and ask them what you ordered, what you have and what your options are, if you want help.

            If it is required to configure RAID1 in hardware then you could ask who ever specified the system or ordered it how they expect that to happen and what they ordered to allow it to happen.

            Hardware RAID is fairly rare in AIX land because the operating system can take care of it for you.

            HTH
          • The_Doctor
            The_Doctor
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            Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

            ‏2013-02-21T12:45:33Z  in response to SystemAdmin
            srangama, in part wrote -> In the server there is a Storage Backplane -- 3 SFF Drives/SATA DVD/ HH Tape (EJ0E), and it has three 300GB 15K RPM SAS SFF disk drives.

            Unbeknown to you, you answered your own question. Buried within your response is feature code EJ0E.

            Feature code EJ0E supports RAID 0, 1, 10. No RAID 5 or RAID 6. So in theory, you could set your environment like you asked in your 1st post:

            • RAID 1 using drives 0, & 1 ..... with drive 2 as a hot spare.

            To do this:

            • obtain the latest standalone AIX Diagnostic CD. Download it if you have to.
            • boot this CD
            • run SAS Disk Array Manager
            • set the array the way you want it, destroying whatever is pre-installed on those drives
            • power down
            • then start your server build

            I've never worked with feature code EJ0E so I caution you:
            • the above is theory based on my understanding of how it works
            • except for educational purposes, the above procedure using only 3 drives, IMHO is a total waste of time. aka... a total PITA

            dukessd steered you correctly. The smarter approach is something like:

            • use these 3 drives as JBOD
            • install VIO Server on drive 0
            • use s/w mirroring to mirror to drive 1
            • then use drive 2 for whatever you want. Using drive 2 as an alt_disk_copy volume might be a consideration. (you'll have to adjust /image.data to use drive 2 as an alt_disk_copy volume but well worth the effort)
            • or better yet, just put everything on a SAN & be done with it.

            Bottom line, do whatever works for you.
            • dukessd
              dukessd
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              Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

              ‏2013-02-21T20:42:23Z  in response to The_Doctor
              Diag CD ISO download:

              http://www-304.ibm.com/webapp/set2/sas/f/diags/download/home.html

              YW
            • DanBraden
              DanBraden
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              Re: How to configure RAID on a P710 where VIOS / IVM is going to be installed?

              ‏2013-05-30T13:48:53Z  in response to The_Doctor

              I kind of prefer creating a RAID 1 array to using LVM mirroring.  The reason is that the SAS RAID manager keeps track of in-flight writes on NVRAM for making the mirrors consistent after a crash while writes were in-flight (so a write might have made it to only one copy which could lead to a problem later), while LVM does this by writing to the outer edge of the logical disk into an area know as the mirror write consistency (MWC) cache.  Thus, mirrored LVM writes generate 4 physical IOs, while writes to RAID 1 arrays creates 2 physical writes. 

              So RAID 1 has a performance advantage, but whether this matters depends on the actual IO workload.