Comments on: IBM FC #4319 disk drives

By: iseriesguy2

iseriesguy2 — Thu, 19 Jan 2006 12:03:01 +0000

My reference has been the system report from performance tools to determine how busy your current drives are. The operations per second on the drives should not exceed 30 on average per drive. It also depends on the IOP you have and how many drives you have on the IOP and the application that’s running on the system. The drive information can also be found on on the system report. If ops per second exceed 30 or are close, adding higher capacity drives on the same IOP will only make matters worse. If this is the case, I would suggest investing $900.00 for a higher cache IOP for the drives and that will alleviate some of the performance botleneck.

By: mrdave60

mrdave60 — Thu, 19 Jan 2006 07:39:21 +0000

Seek times and MTBF numbers for these two types of drives are about the same. I have over 100 of the 35gb drives and average about one failure every 6 or 8 months.

There is a command you can use that will give you an idea if performance will be a problem. It is WRKDSKSTS. There is a column titled % busy. As a rule, this number should not exceed about 30%. I would suggest taking a couple of 15 minute samples at different time of the day to see what your current number is. If you plan on doubling the capacity of the drives you want this number to be less than 15 to 20 percent with the 17bg drives.

Hope this helps.