HP DL380 G7 Disk swap to a HP DL380 G6

I know that G6 box very well and certainly the read performance looks fine, they are after all just two disks R1's so 167MBps seems ok as that drive does about 90Mbps max each in real use. The write speed is a little low I have to say, how's the cache split?

Oh and there's no way in hell any two spinning disks will give you a real 706/622 - maybe it's just hitting the cache? You'd struggle to get a pair of SSDs to that level.

And no, smartarrays are wonderful things - I think you've just got your dell speeds wrong and perhaps the write performance might need a bit of tweaking - try Brent's sqlio guide and come back to us/me (CLICKY)

The HP Smart Array P410 is a fine controller, but you will get poor performance out of it if you don't have the battery-backed or flash-backed cache units installed. The cache makes a tremendous difference in that writes are buffered by the cache memory before being committed to disk. You get the write confirmation to the application without having to incur the latency of the physical disk drives.

Here's a 4GB dd on a similarly-spec'd system (DL380 G7 with 24GB RAM and a p410 with 2 x SAS disks and 1GB Flash-Backed Write Cache). The RAM helps a lot in a test like this, but you get the idea...

[root@xxxx /]# dd if=/dev/zero of=somefile bs=1M count=4096
4096+0 records in
4096+0 records out
4294967296 bytes (4.3 GB) copied, 3.70558 seconds, 1.2 GB/s

But realistically, your write performance with two SAS drives in a RAID 1 on that controller with the appropriate cache should be between a sustained 130-170 megabytes/second. A quick iozone test on the above server configuration shows:

[root@xxxx /]# iozone -t1 -i0 -i1 -r1m -s16g
Write
Avg throughput per process                      =  166499.47 KB/sec
Rewrite:
Avg throughput per process                      =  177147.75 KB/sec

Since you're using ESXi, you can't run online firmware updates. You should download the Current Smart Update Firmware DVD, burn it to disk and make sure your system is patched to a relatively recent level.

Here are the controller's quickspecs: http://h18004.www1.hp.com/products/quickspecs/13201_na/13201_na.html

You will want to purchase one of the following, ranging from $350-$600 US:
512MB BBWC
512MB Flash Backed Write Cache
1G Flash Backed Write Cache

To answer your question, the cache solution will help the most. Additional disks won't make much of a difference until you handle the caching situation.

*Note for other users. If you have cache memory on recent HP controllers with up-to-date firmware, there is a write cache override available if you have RAM on the controller but no battery unit. It's slightly risky, but can be an intermediate step in testing what performance would be like on the way to buying a battery or flash unit.