SUMMARY: T3 arrays & VxVM - Specialist question

From: Smith, Kevin <>
Date: Wed Sep 24 2003 - 08:39:06 EDT
This problem took us and Sun a very long time to sort. It turned out that
the lower revision of Seagate drive firmware has a bug which knocks off the
1GB cache of the T3. The solution was to replace all revision 04 drives with
revision 05. Throughput went from 66MB per sec to 98 MB per sec when all the
high rev. drives were used.

Solution: Dont mix Seagate: ST336605Fdrives with ST336704F in the same T3



4 x T3 trays configured in partner pairs
4 x T3 Lun's configured and showing in Solaris 8
1 x VxVM Volume striped down 4 columns and using all trays 
2 x pairs directly connected to HBA on Fire4810

There are no errors on the T3's or in the syslog. Our problem is read
performance on the volume. It is used for business objects reporting.
3 of the trays have extactly the same disks: 36GB Seagates : ST336605F and
the other tray has 36GB Seagates: ST336704F. 

The follow table shows the performance comparison:

T3 Tray	KB/s	Service (ms)	
T30_0	20447.4	50.2	
T30_1	34317.9	30.4	
T31_0	48971.5	20.9	
T31_1	47174.8	21.7	

This is driving us all round the bend. Can anyone shed some light on why
this is happening. We need to ensure that IO is balanced across all four
trays as it should be with a stripe.

Thanks very much in advance.

Kev Smith 

sunmanagers mailing list
Received on Wed Sep 24 08:38:58 2003

This archive was generated by hypermail 2.1.8 : Thu Mar 03 2016 - 06:43:23 EST