Built-in SCSI interface in rp5470 good enough to host Ultra320 15K rpm drives

[Philip Chan_1]

Hi,

Buying new rp5470 server from HP soon and I'm thinking to fill all 4 internal drive bases with Ultra320 15K rpm SCSI drives. I tend to believe the 2 built-in SCSI interfaces (Ultra2 SCSI?) are not sufficient to handle the maximum thoughtput of these drives when they are all busy at the same time. Would like to get some opinions from you guys on whether faster SCSI interface cards should be added to our server configuration. Comments are all welcome.

Thanks in advance for your help.

Regards
Philip

[Steven E. Protter]

Take a look here:

http://partsurfer.hp.com/cgi-bin/spi/main?sel_flg=partlist&model=RP5470&HP_model=&modname=9000+Server+-+rp5470&template=secondary&plist_sval=ALL&plist_styp=flag&dealer_id=&callingsite=&keysel=X&catsel=X&ptypsel=X&strsrch=

If HP has such a drive, you can install it in your server. If such a drive is part of a drive array, you'll need an appropriate connector, probably fiber.

I believe the built in I/O card on those servers is SCSI 2 Ultra. partsurfer will help you find the specifications you need.

http://partsurfer.hp.com

SEP

[Philip Chan_1]

Hmm... seem like the 36G drives might not be available but I've not receive a "NO" sign from our account manager, let's wait and see.

A minimum of 4 disks is a requirement for us since the server would run Sybase which requires data and log disks to be separated, and mirroring these two disks for redundancy just make it a double. Considering our requirement, having bigger capacity drives is just a waste for us.

[James Murtagh]

Hi Philip,

I think the 72GB drives are available for the rp5470 now. I took a look at Seagate and Maxtor drives of this type and the sustainable internal throughput for them seems to be about 75MB/s. The internal throughput range is 57-86MB/s. So if they are indeed Ultra 2 controllers you have you'll get a maximum of 80MB/s from each one. To get the full throughput from four drives and two controllers it appears you'll need the ultra160 cards. However, Bear in mind that when installed in the server, various other elements come into play so you may not find the controllers to be a bottleneck - maybe some stress testing would be best before purchasing new ones.

cheers,

James.

[Sridhar Bhaskarla]

Hi Pilip,

My understanding is that Ultra-2 scsi (you are right about built-in on L-class) supports a tranfer rate of 40MBPS where as Ultra320 SCSI drives can support upto 320 MBPs. SO, I agree that you will not be able to utilize your drivers completely.

-Sri

[James Murtagh]

The Ultra2 scsi speed was defined in terms of narrow (40MB/s) and wide (80MB/s) but I don't think many devices were made in narrow mode, as it seemed to defeat the purpose of the extra throughput. The cards in the rp5470 will almost certainly be wide so should give 80MB/s. Its confusing in some HP documentation on the cards as they normally do start off stating the 40MB/s transfer rate as "Ultra2" when in fact the cards are wide.

[Philip Chan_1]

I'm a bit surprised knowing that the built-in SCSI interfaces in the rp5470 servers are slower than the SATA interfaces (150MByte/sec per channel if I'm correct) that come with those cheapy Taiwanese mainboards :)

[Steven E. Protter]

In practice you are not gont to get 80 MB/s in those internals.

Based on the data posted here I conclude that a n add in card is required.

partsurfer lists your HP certified options.

Fiber is probably best.

SEP

[Leif Halvarsson_2]

Hi,
Don,t confuse disk thoughtput with bus thoughtput. A Ultra 320 bus can reach 320MB/s in "burst" mode but not a single disk. Also, remember that the specified throuhput for a disk is in "raw" mode, not with a filesystem on it. If I have read the specification for the rp5470 correct there is two separate SCSI buses for the internal disks (two disks on each bus). In practical use, I dont think there will be any problem with four internal Ultra 320 disks.

[Stefan Farrelly]

SEP is dead right. The inernal scsi controllers (ultra wide) on your rp5470 will only do 80mb/s max and the 15k rpm 36GB Ultra160 drives on our superdomes run at 66mb/s sustained each, so putting these (or ultra320 equavilents) on you rp5470 will swamp the bus. You need to add an Ultra160/320 controller to get the most out of the disks you want to add.