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1 Balage commented Permalink

Great article. We just purchased a DS3512. Do you have a guide to set up DS3500 with AIX using iSCSI ? The official "IBM System Storage DS Storage Manager Version 10: Installation and Host Support Guide" only has this very generic paragraph: <br /> "An AIX host system requires either the AIX Redundant Disk Array Controller (RDAC) or the MPIO failover driver for Fibre Channel path redundancy. In supported Veritas environments, RDAC is the supported failover driver." <div>&nbsp;</div> The key piece I'm the most interested in is how to utilize multiple iSCSI ports on the DS to achieve 4Gbps or even 8Gbps bandwidth capability.

2 anthonyv commented Permalink

Interestingly the Redbook says: <br /> page 593: <div>&nbsp;</div> Note: At the time of writing this Redbooks publication, only FC configuration was <br /> supported on AIX. <div>&nbsp;</div> I am unsure if this has changed.

3 Balage commented Permalink

Does that mean that with the DS3500 neither iSCSI nor SAS are supported in AIX? That seems odd. I have iSCSI working fine with NetApp on AIX. Surely the high function SAS adapters on the new Power 7 machines must be supported with IBM DS3500 storage. Surely there is someone at IBM that knows how to make the DS3500 work with AIX. Can you please help solve this mystery?

4 anthonyv commented Permalink

I headed over to the SSIC: <div>&nbsp;</div> <div>&nbsp;</div> I selected Entry Disk --&gt; DS3500 and then any AIX OS version. In each case the only connection protocol supported was Fibre Channel and at higher levels, FCoE. So at this point there is no support for AIX and iSCSI. or SAS. <br /> Which country are you in? Your better to contact your local IBM rep in that country to get access to the support roadmap.

5 Balage commented Permalink

Thank you for that great resource! I'm in the US. I'm working with LSI to figure out if they can provide direct support. In the mean time, looks like the only option for SAS on AIX is to use the disk expansion shelves for specific Power products, and for iSCSI is to use N-series. <div>&nbsp;</div> Would you happen to know of an equivalent of that has the actual information on how to implement the supported solutions listed on the ineroperability web page?

6 anthonyv commented Permalink

In general the short answer is to go to the Redbooks site and find an appropriate Redbook for the relevant product: <div>&nbsp;</div>

7 Vbhand commented Permalink

What is the space overhead for RAID-5, for RAID-6 <br /> over DS3500, and how is it implemented? <div>&nbsp;</div> i.e., is RAID-5 3+1, 4+1, 5+1? <div>&nbsp;</div> is RAID-6 4+2, 6+2.... <br />

8 anthonyv commented Permalink

Your maths is correct. <br /> The effective usable space of a RAID-5 array is the size of the disk (S) x the number of disks (D) minus the capacity of one disk. <br /> So capacity in GB is ((S x D) - S) <div>&nbsp;</div> The effective usable space of a RAID-6 array is the size of the disk x the number of disks minus the capacity of two disks. <br /> So capacity in GB is ((S x D) - 2S)

9 HangaS commented Permalink

Indeed! We just got a dual iSCSI controller DS3524 with 24 600GB disks. <br /> Very easy to deploy and setup. We got it attached using multipath to our two bladecenter E running Xen Virtualizaition in no time! <br /> I was expecting speeds greater than 130MB/s with the 8way multipath setup, tho. <br />