Hi all,

I have a few older dl385 Gen1 systems lying around sporting smart array 6i with 6 146GB scsi 320 10K drives in raid10 using 128bit strip size and 16GB of Ram.

I am using these systems for a GPL Xen cluster for a cloudmin setup and found something puzzling when I started to optimize them.

Running dd I discovered that with my 128mb BBWC module setup I get about 25MB/s sustained write with 100% write and 0% read cache setup.

However, when I turn OFF Array Accelerator my sustained performance jumps up to 110MB/s.

I have been all over looking at horrible write performance posts but the solution was to turn on the Cache...

Perhaps I have a faulty BBWC module but it checks out ok per the hpacucli tool :


hpacucli ctrl all show detail

Smart Array 6i in Slot 0 (Embedded)
Bus Interface: PCI
Slot: 0
Cache Serial Number: P9A3A0A9STD0A8
RAID 6 (ADG) Status: Disabled
Controller Status: OK
Hardware Revision: Rev B
Firmware Version: 2.84
Rebuild Priority: Low
Expand Priority: Low
Surface Scan Delay: 15 secs
Surface Scan Mode: Idle
Post Prompt Timeout: 0 secs
Cache Board Present: True
Cache Status: OK
Accelerator Ratio: 0% Read / 100% Write
Total Cache Size: 192 MB
No-Battery Write Cache: Disabled
Cache Backup Power Source: Batteries
Battery/Capacitor Count: 1
Battery/Capacitor Status: OK
SATA NCQ Supported: False



I am running the noop io scheduler in Centos 5.9 x86_64 with XEN kernel started with 1024 ram for Dom0.

uname -a
Linux xen0.cloudmin.local 2.6.18-348.18.1.el5xen #1 SMP Thu Sep 26 15:42:15 EDT 2013 x86_64 x86_64 x86_64 GNU/Linux


Here is a DD example (3 * Ram) with Array Accelerator turned OFF
######################################################
hpacucli controller slot=0 show status

Smart Array 6i in Slot 0 (Embedded)
Controller Status: OK
Cache Status: Not Configured
Battery/Capacitor Status: OK


dd if=/dev/zero of=ddfile1 bs=1M count=3000
3000+0 records in
3000+0 records out
3145728000 bytes (3.1 GB) copied, 33.9622 seconds, 92.6 MB/s


Here is a DD example with Array Accelerator turned ON
######################################################
hpacucli controller slot=0 logicaldrive 1 modify arrayaccelerator=enable

hpacucli controller slot=0 show status

Smart Array 6i in Slot 0 (Embedded)
Controller Status: OK
Cache Status: OK
Battery/Capacitor Status: OK

dd if=/dev/zero of=ddfilenoopcache bs=1M count=3000
3000+0 records in
3000+0 records out
3145728000 bytes (3.1 GB) copied, 197.085 seconds, 16.0 MB/s




I installed the WWBC module with hopes of getting the most out of these systems but I am flabbergasted at the horrible sustained Writes.

Thoughts?