RE: iSeries and Sans

Has somebody priced what it would take to beef up your i5 to be a SAN?

We did, (albeit, we have an i5 520, and wanted to go to 14TB)....
It was in no way financially possible....

Gerald





-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Larry Bolhuis
Sent: Friday, October 27, 2006 3:36 PM
To: Midrange Systems Technical Discussion
Cc: Mark Phippard; Cole Royal
Subject: Re: iSeries and Sans

Mark,
 
 I disagree! It's simple to add another expansion unit, even without 
powering down the system and creating a new partition!

 Switching tapes isn't hard but it takes a bit of coding. In any case I 
don't think that's your big issue here.

 Technology would be iSCSI. Both Copper and Fiber are supported but 
1Gbps is the rate. However if the speed is an issue you can gang up 
multiples.

 As for processor and memory for iSCSI in the i5 hosting partition:.

    Rules of Thumb:   21MB in the Machine pool for each target HBA plus 
1MB for each NWSD
                                Also a meg or so in the Base pool for 
each HBA and 0.5MB for each NWSD
                                Also 0.5Meg or so in the QFPHIS Priave 
pool and 1.0MB for each NWSD.

    In other words for each iSCSI Card add about 22.5MB and for each 
NWSD about 2.5MB to that partition.  It is critical to have enough 
machine pool memory just like any other partition!!

    Now for CPU it's done per K of disk IOs from the WinDOZE box. For 
each Thousand disk I/O per second, about 190 CPW is required.  This 
assumes a standard mix of 35% writes 65% reads and an average I/O size.

    I can't speak to reliability directly but the i is very reliable so 
I wouldn't think it would be much different than the SAN.


     - Larry

Mark Phippard wrote:

That is all fine if you configure your box that way to begin with, but

it 

is not easy to retrofit a box to this sort of setup.  Is there any

kind of 

guidance or wisdom as to how much CPU and memory a partition like this

needs?

Backup is a bit of an issue.  Moving a tape drive between partitions

can 

work, but not something I'd want to rely on, so you probably need tape

drives for each partition.  Of course you do for a SAN too, but there

is 

no savings here.

Finally, what technology would the iSeries be using for the SAN

feature? 

iSCSI?  How does that compare to the typical Fibre Channel-based SAN

for 

performance and reliability?

Mark