FS System: What do Hosts Report When a Thinly Provisioned Volume has Reached Threshold Limit

Asset ID:	1-72-2002598.1
Update Date:	2018-01-03
Keywords:

Solution Type Problem Resolution Sure

Solution 2002598.1 : FS System: What do Hosts Report When a Thinly Provisioned Volume has Reached Threshold Limit

Applies to:

Oracle FS1-2 Flash Storage System - Version All Versions and later
Information in this document applies to any platform.

Symptoms

When a thinly provisioned LUN on a FS Flash Storage System cannot be extended, the following messages will typically be recorded on the host.

Solaris OS:

Apr 15 06:29:51 hostname scsi: [ID 107833 kern.warning] WARNING: /scsi_vhci/disk@g6000b08414b303032363932323600014 (sd5):
Apr 15 06:29:51 hostname         Error for Command: write(10)               Error Level: Retryable
Apr 15 06:29:51 hostname scsi: [ID 107833 kern.notice]   Requested Block: 2305228777                Error Block: 2305228777
Apr 15 06:29:51 hostname scsi: [ID 107833 kern.notice]   Vendor: Oracle                             Serial Number:
Apr 15 06:29:51 hostname scsi: [ID 107833 kern.notice]   Sense Key: Media_Error
Apr 15 06:29:51 hostname scsi: [ID 107833 kern.notice]   ASC: 0xc (write error - auto reallocation failed), ASCQ: 0x2, FRU: 0x0

Linux OS:

Apr 15 06:29:51 hostname kernel: sd 2:0:0:5: [sdf] Unhandled sense code
Apr 15 06:29:51 hostname kernel: sd 2:0:0:5: [sdf]
Apr 15 06:29:51 hostname kernel: Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
Apr 15 06:29:51 hostname kernel: sd 2:0:0:5: [sdf]
Apr 15 06:29:51 hostname kernel: Sense Key : Medium Error [current]
Apr 15 06:29:51 hostname kernel: sd 2:0:0:5: [sdf]
Apr 15 06:29:51 hostname kernel: Add. Sense: Write error - auto reallocation failed

System events are logged prior to storage capacity nearing threshold limit:

2015-04-15T05:33:46.447 STORAGE_POOL_NEARING_ALLOCATION_LIMIT WARNING ComponentName=/Storage Domain 1

System events are logged when storage capacity reaches the threshold limit:

2015-04-15T06:08:46.574 STORAGE_POOL_REACHED_ALLOCATION_LIMIT WARNING ComponentName=/Storage Domain 1

Cause

Traditionally, when a system allocates storage for a logical volume, the allocation is dedicated to that volume. This dedication prevents other volumes from accessing this storage, even when the amount that is allocated is never used by the owning volume.

Thin provisioning allows you to leverage this unused storage. To leverage unused storage, perform the following actions:

Allocate capacity based on future needs.
Draw from a common pool of storage as the allocated capacity is consumed.

Thin provisioning on an Oracle FS System allows the creation of a logical volume of any size without committing the requested capacity at the time opf creation. Each volume appears to have all of the storage that the volume needs for ongoing operations. The difference is that the physical capacity is not actually locked to a particular volume. All logical volumes in an Oracle FS System have two properties that are related to the logical capacity of the volumes. Also, whether a logical volume is thinly provisioned depends on the relationship between the initial values of those two capacities.

If the Storage Domain containing the volume on the Oracle FS System becomes full, host writes to previously unwritten areas on the LUN will fail because the thinly provisioned volume cannot be extended as there is not enough physical storage available.

For further information on thin provisioning, refer to the Oracle Flash Storage System Administrator's Guide.

Solution

Install additional Drive Enclosures to increase physical storage capacity of the Storage Domain.

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