Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 Server: A Slower Hard Disk was Sent as a Replacement

Asset ID:	1-72-1981543.1
Update Date:	2017-10-05
Keywords:

Solution Type Problem Resolution Sure

Solution 1981543.1 : Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 Server: A Slower Hard Disk was Sent as a Replacement

Applies to:

Sun SPARC Enterprise M5000 Server - Version All Versions and later
Sun SPARC Enterprise M8000 Server - Version All Versions and later
Sun SPARC Enterprise M9000-32 Server - Version All Versions and later
Sun SPARC Enterprise M9000-64 Server - Version All Versions and later
Sun SPARC Enterprise M3000 Server - Version All Versions and later
Information in this document applies to any platform.
This document applies to all internals disks for the Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 Servers. Example data shown will be of a Sun SPARC Enterprise M3000 server.

Symptoms

My Sun SPARC Enterprise M3000 has a broken internal 146GB - 10000 RPM SAS Disk Assembly . My server had 4 x FUJITSU-MBD2147RC-3701, but Oracle Support sent me a FUJITSU-MBB2147RC-3703 as a replacement disk:

AVAILABLE DISK SELECTIONS:
0. c0t0d0 <FUJITSU-MBD2147RC-3701 cyl 14087 alt 2 hd 24 sec 848>
/pci@0,600000/pci@0/pci@0/scsi@0/sd@0,0
1. c0t1d0 <FUJITSU-MBB2147RC-3703 cyl 14087 alt 2 hd 24 sec 848>
/pci@0,600000/pci@0/pci@0/scsi@0/sd@1,0
2. c0t2d0 <FUJITSU-MBD2147RC-3701-136.73GB>
/pci@0,600000/pci@0/pci@0/scsi@0/sd@2,0
3. c0t3d0 <FUJITSU-MBD2147RC-3701-136.73GB>
/pci@0,600000/pci@0/pci@0/scsi@0/sd@3,0

FUJITSU-MBD2147RC-3701 disks are capable of using a 6Gbps data-transfer rate, where as the FUJITSU-MBB2147RC-3703 is only capable of a 3Gbps data-transfer rate.
This slower disk will slow down my zpool access times, I need a like for like disk replacement.

Cause

To ensure long term Field Replacable Unit (FRU) availability, over time the underlaying physical part for a certain FRU can change. Secure documentation and extensive test procedures do ensure that when a specific FRU needs to be replaced, its critical functionality matches that of the part is it replacing.

The limiting factor for data transfer rates to the internal hard disks in the Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 Servers is the used LSI Serial Attach SCSI (SAS) chip:

Sun SPARC Enterprise M3000 server is using the LSI SAS 1068E
Sun SPARC Enterprise M4000/M5000 server is using the LSI SAS 1064
Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 server is using the LSI SAS 1064

Both LSI SAS 1068E and LSI SAS 1064 have a maximum data transfer rate of 3Gbps.
The slower transfer rate of the replacement disk is therefore not a limiting factor for the zpool access times, since the 6Gbps capable disks have been running at a maximum data transfer rate of 3Gbps due to the LSI SAS chip limitations.

Solution

With the uses LSI SAS chip being the limiting factor in data transfer rate, the replacement disk is fully functional and matches the performances specifications of its failing predecessor. No further action is needed.

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