Flashes (Alerts)
Abstract
Data read may be corrupted (zeros instead of actual data) on IBM Storwize V7000 Unified (V7000U) cache cluster in the Remote Caching (WAN caching) setup when the home cluster is running Tivoli Storage Manager HSM recalls. Data residing on the home cluster is not corrupted.
Content
Symptom
Data presented to applications may contain zeroes instead of the actual data from the cache cluster.
Environment
In the Remote Caching setup, data from Storwize V7000 Unified home cluster that needs to be recalled from Tivoli Storage Manager HSM and that are read from Storwize V7000 Unified cache cluster may trigger the unexpected data issue.
Note: Data is not corrupted within the Storwize V7000 Unified home cluster, but may be corrupted in the cache cluster.
Diagnosing the problem
The issue resides in the operating system used in Storwize V7000 Unified.
1. Check if the home cluster is configured for Remote Caching setup, by running "lswcachesource".
a) If there is no filesystem configured for Remote Caching, there is no action needed.
The following example shows the home cluster not configured:
#lswcachesource
EFSSG0100I There are no values to return.
b) If there is a filesystem configured for Remote Caching, go to step 2
The following example shows the home cluster is configured:
#lswcachesource
WCache-Source Name WCache-Source Path ClientClusterId ClientClusterName WCache-Source Access Mode Is Cached
testing3_home_default "/ibm/gpfs0/testing3_home_default" 12402814423331849038 st002.virtual1.com ro no
trial_ro /ibm/gpfs0/trial_ro 12402814423331849038 st002.virtual1.com ro no
EFSSG1000I The command completed successfully.
2. Check if the home cluster is configured with HSM by running "lshsmstatus"
a) If the HSM status shows not configured, there is no action needed.
The following example shows HSM is not configured:
[YourCluster]$ lshsmstatus
This cluster is not configured for HSM. Exiting.
EFSSG1000I The command completed successfully.
b) If the HSM status shows configured, go to step 3
The following example shows HSM is configured:
[YourCluster]$ lshsmstatus
Global Status
Node Daemons Recall Migrate Failover Filesystem(s)
(Rec-#) (Migr-#) (Owned)
3. Contact IBM for the action to disable HSM recall or disable Remote Caching.
4. The Storwize V7000 Unified systems will check for the existence of HSM and Remote Caching functions configured on the same cluster. If the system finds that both functions are configured, the system will post an event 100001 in the GUI and call home to IBM support with the problem record (PMR) if the call home function is enabled.
Resolving the problem
This issue is fixed with Storwize V7000 Unified V1.4.2.0. Please upgrade to Storwize V7000 Unified V1.4.2.0 or later version.
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Document Information
Modified date:
25 September 2022
UID
ssg1S1004375