![]() If information that is written to the disk is changed during the process of failover, it might cause issues for users or software that requires this information. If disk failover occurs but the server that takes ownership of a disk cannot read it, the cluster cannot maintain availability of the disk. The test also validates that information written to each disk before a failover is the same after the failover. Specifically, the test validates that even when multiple disk failovers occur simultaneously, any clustered server that takes ownership of a disk can read it. Validates that simultaneous disk failovers work correctly in the cluster. In addition, disks are never left in an unprotected state, which lowers the risk of volume corruption. ![]() Therefore, a failover cluster can be more responsive in a variety of situations, unlike a cluster running an earlier version of the operating system. Because the Persistent Reserve commands avoid SCSI bus resets, they are much less disruptive than the older reserve/release commands. Validates that the cluster storage uses the more recent (SCSI-3 standard) Persistent Reserve commands, which are different from the older SCSI-2 standard reserve/release commands. Validates that the storage supports necessary SCSI inquiry data as well as Vital Product Data (VPD) descriptors, and that they are unique. Validate SCSI Device Vital Product Data (VPD) ![]() If multiple servers own a disk at the same time, they might perform write operations in an uncoordinated way, possibly corrupting the disk. Failover clusters are designed to operate in circumstances where only one clustered server at a time owns a disk. If multiple clustered servers obtain ownership of a cluster disk through disk arbitration, the disk might become corrupted. Validates that when multiple clustered servers arbitrate for a cluster disk, only one server obtains ownership. Validates that multi-path disks (Microsoft Multipath I/O-based disks,) have been configured correctly for failover cluster. Validates that the file system on disks in shared storage is supported by failover clusters. In either case, if the affected disk is a witness disk, (a disk that stores cluster configuration data and participates in quorum,) such issues could cause the cluster to lose quorum and shut down. If information written to the disk is changed during the process of failover, it might cause issues for users or software that require this information. The test also validates that information written to the disk before the failover, is still the same after the failover. Specifically, the test validates that when a disk owned by a clustered server is failed over, the server that takes ownership of the disk can read it. ![]() Validates that disk failover works correctly in the cluster. When a particular server owns a disk, if one or more other servers arbitrate for that disk, the original owner retains ownership.Each of the clustered servers can use the arbitration process to become the owner of each of the cluster disks.Another possible result is that the application attempting to access the disk might appear to have failed, and the cluster might initiate a needless failover. If disk read/write operations take too long, one possible result is that cluster time-outs might be triggered. Validates that the latency for disk read/write operations is within an acceptable limit for a failover cluster. In addition, the test validates that multipath I/O is working correctly, which means that each of the disks is seen as one disk, not two. To support clustering, the disk must be connected through Serial Attached SCSI (SAS), iSCSI, or Fibre Channel. Lists disks that can support clustering, and are visible to all tested servers. Disks that can support clustering and can be accessed by all the servers.Lists all disks that are visible to one or more tested servers. The Validate a Configuration Wizard performs the following storage validation tests: These tests are comprehensive however, some specific tests may not run after the cluster is running nor in a multi-site cluster. The storage tests list and test the capabilities of all disks available to the cluster.
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