PowerStore: Migrating VMs to a filesystem of type “VMware File System” raises an alert fs_blockio_not_match_allocaton_size

Migrating virtual machines (VMs) to a datastore that is located on a PowerStore filesystem of type “VMware File System”, raised alert fs_blockio_not_match_allocaton_size.

The alert 0x01301A01 (SDNAS_FS_BLOCKIO_FS_BLOCKIO_NOT_MATCH_ALLOCATON_SIZE) with the alert text "File system <fsname> in NAS server <vdmname> I/O patterns do not match the allocation size (<actualSize> bytes)".
Also, the alert 0x01301A03 (SDNAS_FS_BLOCKIO_FS_BLOCKIO_NOT_ALIGNED) with the alert text "File system <fsname> in NAS server <vdmname> I/O patterns are not aligned with the allocation size ( <actualSize> bytes)" may be raised.

 

fs_blockio_not_match_allocaton_size is returned when I/O patterns do not match the defined FS allocation size that was set during filesystem creation. 
By default, “VMware File Systems” type filesystems on PowerStore are created with an 8KB allocation unit size as this is deemed general best practice for typical VMware workloads. However, migration activities can generate significant amounts of larger I/Os that can trigger the alert.

If it is expected that I/O sizes will be larger during normal workloads then this value can be adjusted during file system creation with the available I/O sizes being 8KB, 16KB, 32KB, and 64KB.

During migration activities, it can be expected that I/O workloads use much larger block size activity than expected during normal activity. Therefore, it is best to wait until all migration activities are done to see if the messages continue.
It is likely that the I/O pattern during storage vMotion is such that it is triggering the event and can be safely ignored assuming alerts are not frequently seen during normal production workloads. Note, however, that these alerts are simply informative and do not indicate a problem if performance is not affected.

If the issue persists, contact technical support.