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Forgive me, my muddled brain was confusing parity sets with ASP's here. Just ignore everything but the last sentence.... Regards, Scott Ingvaldson AS/400 System Administrator GuideOne Insurance Group -----Original Message----- From: Ingvaldson, Scott Sent: Monday, October 27, 2003 4:11 PM To: 'midrange-l@xxxxxxxxxxxx' Subject: RE: Exposure with unprotected disk units You probably "could" add the 17.5 G drives to the parity set with the 4 G units, but I don't think that you'd want to. We had a single 2 G drive in a parity set with 8 G drives once and the 2 G drive got overworked and killed the I/O in that set. I was told that the rule of thumb was not to mix drives more than 1 step apart in a parity set. Of course the rules could be different now but I would think that they would be more dependant on the disk controller than the drives themselves. If you had a parity set with 8.5 G drives in it I wouldn't hesitate to add the 17.5's to it. Other options would be to buy two more 17.5's to add to this set and start parity protection (you'll lose 25% of the total DASD) or just start mirroring and lose 50% (you'd be at 37.2% in this ASP.) Regards, Scott Ingvaldson AS/400 System Administrator GuideOne Insurance Group -----Original Message----- date: Mon, 27 Oct 2003 13:47:41 -0600 from: "Scott Lindstrom" <SLindstrom@xxxxxxxxxx> subject: Exposure with unprotected disk units In reviewing one of the old systems I am responsible for, I noticed that some 17.54gb disk units were added onto the system (as ASP 3) and are in an unprotected state. I think if we had added 4gb disk units in these locations, we simply could have added them to the existing parity set, but since they are 17.54gb they can't be added. Is this correct? Size % I/O Request Read Write Read Write % --Protection-- Unit Type (M) Used Rqs Size (K) Rqs Rqs (K) (K) Busy ASP Type Status 1 6607 4194 84.8 .5 10.3 .3 .2 12.5 6.7 0 1 DPY ACTIVE 2 6607 3670 84.7 .5 15.3 .3 .2 18.6 11.4 0 1 DPY ACTIVE 3 6607 3670 84.7 .5 18.2 .2 .2 24.0 10.9 0 1 DPY ACTIVE 4 6607 3670 85.0 .5 11.7 .3 .2 17.2 4.9 0 1 DPY ACTIVE 17 6607 3145 23.8 .0 5.4 .0 .0 4.0 5.9 0 2 DPY ACTIVE <snip> 23 6714 17548 18.6 .1 56.9 .1 .0 66.8 37.4 0 3 24 6714 17548 18.6 .2 67.6 .1 .0 76.6 50.2 0 3 What could I expect if we lost either drive 23 or 24? Can the system ride out the loss of a user ASP? If not, and it crashes, when the failed disk is replaced and the system is brought back up, is there any data loss in the ASPs that *are* RAID protected? (This is a V4R4 system). Scott Lindstrom This message and accompanying documents are covered by the Electronic Communications Privacy Act, 18 U.S.C. §§ 2510-2521, and contains information intended for the specified individual(s) only. This information is confidential. If you are not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, copying, or the taking of any action based on the contents of this information is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail, and delete the original message.
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