How fast should my Xserve RAID be?

[Jeremy Garchow]

they seem slow to me. How big is your drive and how many of the drive trays are populated?

[Herb Sevush]

Dave –

I use the Blackmagic tests, which are a little different, but I get Reads and Writes around 170 – 210. This is with a fully populated Xraid with each side set up as raid 5 and both sides striped together as a single raid 0 (this is often referred to as raid 50). How is your Xraid configured?

Herb Sevush
Zebra Productions

[Dave Teixeira]

Just put in 7 new 500GB drives into the left side (slots 1-7).
There is nothing on the drives.
The other side of the RAID (slots 8-14) are being used as a separate RAID.

I followed AJA’s spec sheet for setting up the new RAID.
Strip 5
OSX Extended (not Journaled)
Allow Host Cache Flushing is disabled

[Dave Teixeira]

I do have the left and right sides of the Xserve being used as separate RAIDs. So they are not striped together as 50.
I realize this will cause the transfer rates to be slower but I was not expecting it to be as slow as my test results.

[Jeremy Garchow]

If you are using half of the Raid in a single channel configuration, that seems about right to me. The Xriad tops off at around 200 MB/sec protected so about half of that is what you are seeing.

[Dave Teixeira]

Thanks Jeremy,
That makes since!

[Bob Zelin]

Hi –
two internal SATA drives striped RAID 0 will give you about 120mb/sec. The Apple XServe RAID is a piece of crap. I have seen performance with 14 drives as low as 90mb/sec (and to be fair as high as 220mb/sec when it is new). The Apple XServe RAID is old technology. I am sorry that you put more money into it. There are fantastic new products on the market from Dulce, Cal Digit, Maxx Digital, Sonnet, G-Tech, ProMax, etc., but the XServe RAID is not one of them. You can do better with two cheapo internal SATA drives striped RAID 0.

Bob Zelin

[Robert Leong]

[Dave Teixeira] “I looked on the web to see if I could find anything to compare my speed test to, but could not find anything.
Do these speeds seem about what I should be getting.”

Hi Dave, here is a performance map for comparison:
https://www.dulcesystems.com/html/prodqperfmap.html

It is based on our PRO DQ a SATA PCI-e based RAID, the map shows from empty to full and all major RAID levels. Tested on Mac Pro and KONA 3. Very fast and it’s based on 8 drives only.

The other end of the spectrume is a 4 drive setup, the Quad:
https://www.dulcesystems.com/html/quadperf.html#MAP

Still respectable on just four drives and in RAID 5 protected mode too.

Your setup with 7 drives as one RAID 5 connected to a computer with a 2Gb Fibre connection would max out at a theoretical maximum of 200MB/s or so, in real life it would be 20% less then that or more. So the numbers looks a little slow and could be due to older technology on the XRAID as Bob Z had mentioned. Oh, the brand of drives contributes to this too.

Robert Leong / Dulce Tech Support

[Debbi Mita]

For maximum performance, you need to set the “Read Prefetch” to 8 stripes (512 MB per disk), also enable Apple Drive Module (ADM) Drive Cache and Write caches.
Disable “Use Steady Streaming Mode” may give you better performance too.

To compare the speed, if you google online, you may fine an interesting aricle about Xserve RAID vs. Caldigit HDPro:

https://www.geekymac.com/?p=528

it should cover everything you want to know.

[Dave Teixeira]

Thanks everyone!
Great input. Gives me somethings to think about for the future.
DT