Re: Will mixing 775 SSD and 177 SSD in a 5887 EXP24S I/O drawer be a potential performnace issue

In the first scenario you would absolutely want to add those disks to the ASP AND BALANCE before you create the large new PF. This will not eliminate the problem because as you say they ARE larger and will certainly garnish more I/O but at least they will not get ONLY new (and likely Hot) data.

The other option is to replace all the disks with the large ones. :-)


- Larry "DrFranken" Bolhuis

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On 12/21/2014 10:39 PM, Steinmetz, Paul wrote:

On a P7, 740 8205 E6C, I currently have 18 177 SSF-2 SSD (2844 gb; 5913 controllers) in a 5887 EXP24S I/O drawer, which is 100% of my production LPAR, CEC is not used for this LPAR.
We need to add disk for a few new PF and LF that will take a large amount of DASD.
I have 6 empty disk slots in a 5887 EXP24S I/O drawer.
I was planning on adding 6 775 SSF-2 SSD (3875 gb), one new RAID-5 parity set.

1) I could add these 6 drives to the current sys ASP.
These 6 drive would be accessed much more heavily because of the large difference in size.
Could this be a potential performance issue, because these would be "hot drives"?
"Hot drives" with SSD would not be as noticeable as with spinny hot drives.

Or,
2) I could create a new ASP for these 6 drives, and then place only these new files in this ASP.
Still have the hot drive issue, but less impact.

3) Are there other options??

Thank You
_____
Paul Steinmetz
IBM i Systems Administrator

Pencor Services, Inc.
462 Delaware Ave
Palmerton Pa 18071

610-826-9117 work
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