Before you start IBM Spectrum Virtualize update preparation, check the following items for  every server that is attached to IBM Spectrum Virtualize that you update: For information about troubleshooting, see these websites (require an IBMid): Fix every problem or “suspect” that you find wi th the disk path failover capability. Because a  typical IBM Spectrum virtualize environment has several dozens of servers to a few hundred  servers attached to it, a spreadsheet might help you with the Attached Hosts Preparation  tracking process. If you have some host virtualization, such as VMware ESX, AIX LPARs, IBM  VIOS, or Solaris containers in your environment, verify the redundancy and failover capability  in these virtualization layers. IBM SAN Volume Contoller Troubleshooting IBM Storwize V7000 Troubleshooting As critical as with the attached hosts, the attached storage controllers must correctly handle  the failover of MDisk paths. Therefore, they must be running supported microcode versions  and their own SAN paths to IBM Spectrum Virtualize must be free of errors. If you are using symmetrical, redundant, independent SAN fabrics, preparing these fabrics for  an IBM Spectrum Virtualize update can be safer than hosts or storage controllers. This  statement is true assuming that you follow the guideline of a 30-minute minimum interval  between the modifications that you perform in one fabric to the next. Even if an unexpected  error brings down your entire SAN fabric, the IBM Spectrum Virtualize environment must  continue working through the other fabric and your applications must remain unaffected. Because you are updating your IBM Spectrum Virtualize, also update your SAN switches  code to the latest supported level. Start with your principal core switch or director, continue by  updating the other core switches, and update the edge switches last. Update one entire fabric  (all switches) before you move to the next one so that any problem you might encounter  affects only the first fabric. Begin your other fabric update only after you verify that the first  fabric update has no problems. If you are not running symmetrical, redundant independent SAN fabrics, fix this problem as a  high priority because it represents a single point of failure (SPOF). Check the compatibility of your target IBM Spectrum Virtualize code level with all components  of your SAN storage environment (SAN switches, storage controllers, server HBAs) and its  attached servers (operating systems and eventually, applications). Applications often certify only the operating system that they run under and leave to the  operating system provider the task of certifying its compatibility with attached components  9.4.7 SAN components update sequence 9.4.6 SAN fabrics preparation 9.4.5 Storage controllers preparation GLYPH<SM590000> The operating system type, version, and maintenance or fix level GLYPH<SM590000> The make, model, and microcode version of the HBAs GLYPH<SM590000> The multipath software type, version, and error log GLYPH<SM590000> The IBM Support page on SAN Volume Controller Troubleshooting: GLYPH<SM590000> The IBM Support page on Storwize V7000 Troubleshooting: 412  IBM System Storage SAN Volume Controller, IBM Storwize V7000, and IBM FlashSystem 7200 Best 