Extended reboot time after a firmware upgrade on systems with a storage pool using more than 64 drives for QSM 4.0.3 and earlier #

If your system is running QSM 4.0.3 or earlier and has a storage pool created with more than 64 drives, it may take up to one hour to reboot after a firmware upgrade.

Before upgrading, check the number of drives in each storage pool and allow sufficient time for the reboot.

Why Does a Storage Pool Enter a Failed State After SAS Cables Are Replaced One at a Time? #

Applies to: QSM 4 systems connected to Western Digital Ultrastar® Data60 or Data102 JBOD enclosures.

When a SAS cable is reconnected, the system may require additional time to rediscover drives in Western Digital Ultrastar® Data60 and Data102 JBOD enclosures. Disconnecting another SAS cable before drive discovery is complete may cause the storage pool to enter a failed state. Therefore, if all SAS cables need to be replaced, we recommend scheduling a maintenance window and performing the replacement with the system powered off, rather than replacing the cables one at a time while the system is running. For connection requirements and supported configurations, refer to the Connect to Western Digital Ultrastar® Hybrid Storage Guide.

What will happen if QCompact trial license expired?  #

QCompact provides deduplication and compression to improve storage efficiency. When the trial license expires, the storage pool continues to operate, but deduplication is disabled.

To re-enable deduplication, a reset is required before applying a valid trial license or a full QCompact license. Contact QSAN Support for assistance with the reset procedure.

ReTrim Errors and Space Reclamation Limitations on Windows iSCSI Volumes #

When running ReTrim on an iSCSI volume backed by a thin-provisioned pool in Windows Server 2022, the operation may fail with the following error: “Neither slab consolidation nor slab analysis can run if slabs are less than 8 MB.” This issue has been resolved in QSM 4.3.0. Upgrade to QSM 4.3.0 or a later supported version, then run the following command in PowerShell with administrator privileges. Replace Z with the actual drive letter:

Optimize-Volume -DriveLetter Z -ReTrim -Verbose

Even after ReTrim completes successfully, the amount of physical space reclaimed may vary depending on the file system and data layout. In testing, most space was reclaimed after deleting large files exceeding 1 GB on NTFS volumes, while reclamation was less effective for small files. On ReFS volumes, most space was reclaimed after deleting both small and large files.

QSM thin provisioning allocates physical space in 1 GB chunks. A chunk cannot be reclaimed in full while it still contains allocated data or file system metadata, such as the NTFS Master File Table (MFT). As a result, a small amount of remaining metadata may prevent an entire chunk from being released, even after the associated files have been deleted.

Monitor physical capacity usage in QSM to verify space reclamation. For workloads with frequent small-file deletion and space reclamation requirements, consider ReFS where supported by your applications and environment. Actual reclamation results may vary.