SAS drives - DP or SP?

[Nick Walton]

Hi,

I'm trying to specify a new ML350 G5 server and planning to fit 2.5" hot plug SAS drives. When I look at the QuickSpecs for the server there seem to be two versions of each drive available: SP (Single Port) and DP (Dual Port). There is no explanation of this in the QuickSpecs for the drives.

Can anyone help me decide which drives to specify and what is the difference or benefits of SP or DP versions?

Thanks in advance!

[Igor Karasik]

Hi,
It depends on your needs
But I think for ML350 SP drives is good enough
http://h18004.www1.hp.com/products/servers/proliantstorage/serial/sas/questionsanswers.html#5b

[KarloChacon]

hi

check also this

SAS dual porting capability and the ability to support I/O requests from more than one controller at a time (multi-initiator) also enables the design of dynamic load
balancing systems and redundant path configurations to further increase performance and reliability.

http://www.fujitsu.com/downloads/COMP/fcpa/hdd/sff-sas_wp.pdf

http://www.wwpi.com/index.php?option=com_content&task=view&id=853&Itemid=44
regards

[Patrick Terlisten]

Hello,

sorry for hi-jacking this thread. :)

IMHO is a Smart Array controller not able to use a dual-ported drive, right? So dual-port drives in a normal ProLiant Server doesn't have a benefit. Which enclosures support dual port drives, or in which systems do I have a benefit from dual-port drives?

Thanks for advice.

Best regards,
Patrick

[Jeremy Peake · Accepted solution]

here is from a source at HP (to the other poster, you get no gain from using the DP drives in a ProLiant server, no harm either):

the dual port sas drives are the "next gen" sas drives. Since it would be too confusing for customers to have both a single port and dual port sas offering, you will most likely see all single port sas drives eventually going EOL and the dual port sas drives being the dominant drive technology moving forward. The real benefits of dual port sas drives will be for the new shared storage blade (SB2000c w/ SB50c) and MSA2000 Family of storage products. These products will allow for dual domain active/active controller technology. You will see many new storage products coming on the scene over the next 6-8 months that will be "dual domain sas". It's the next big thing ;)

As far as using two controllers today for dual port sas drives....not supported since we don't have any "dual domain" sas drive enclosures yet. The MSA60 and MSA70 will be revamped over the next 6 months to introduce "dual domain" functionality, but mainly for expansion enclosures for the SB2000c and MSA2000 storage array products.

[Patrick Terlisten]

Normal SAS drives in a MSA2000? AFAIK is the MSA2000 using propertery "MSA SAS drives". Take a look at the quickspecs, that is my source for that information.

I hope that HP will consolidate there disk drives. A few years ago it was so simple - Universal disk drives for Storage and servers. Today? 2,5" and 3,5" SAS, 2,5" and 3,5" SATA, 3,5" FC, 3,5" SAS and SATA for MSA2000, different speed and size...

Best regards,
Patrick

[Nick Walton]

Thanks for the input here. The answer was that DP drives are coming but are of no benfit in current generation Proliant servers. I have ordered SP drives on that basis.

Thanks again,

Nick.