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Early on we moved from 4GB to 8GB disks. Later, and after adding several more arms, we went from 8GB to 17GB. And added more. DASD throughput has been one of our major bottlenecks (CPU & the SPD bus are the others; RAM has mostly been fine). On our Dev/DR box we started with 8GB disks but again swapped them for 17s. Swapped again for 15K BCC disks. Our CE did a real gig-mig when we upgraded it from a 720 to an 830 as the load source moved to a new disk in the new CEC (the 720 frame became a migration tower). Since 1997, the production system has gone from a 620 uni to a 2-way to a 730 2-way to a 4-way and, shortly, to an i5 570 which we just ordered. We keep upgrading to 2-3x the CPWs but each time it gets sucked up by workload increases within 2 years. Which, I suppose, is a good thing. The i5 upgrade is actually a box swap - new serial number. The only 'upgrade' is the transfer of some LPPs. The 620 started with 8 disks; we now have 62 but the i5 will reduce that to 54 (all 15K 70GB disks on 2780 controllers). With the new box DASD utilization will start under 20% and I have very high expectations on throughput. BTW, the i5 CEC + 4 0595s (to hold the disks) + HMC w/flat panel + dual-LTO2 tape drives + external DVD-RAM for 2nd LPAR all fit in one rack. The Dev/DR box hasn't seen as much action; just from a 720 uni to a 2-way 830. Hopefully I can take it to an equivalent-capable (via CUoD) i5 next year. John A. Jones, CISSP Americas Information Security Officer Jones Lang LaSalle, Inc. V: +1-630-455-2787 F: +1-312-601-1782 john.jones@xxxxxxxxxx -----Original Message----- From: Chuck Lewis [mailto:clewis@xxxxxxxxxx] Sent: Wednesday, November 17, 2004 9:28 AM To: 'Midrange Systems Technical Discussion' Subject: RE: How to perform a GIG MIG Wow - 4 or 5 times in the last two years. Things sure aren't boring for YOU John :-) Chuck -----Original Message----- From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jones, John (US) Sent: Wednesday, November 17, 2004 9:36 AM To: Midrange Systems Technical Discussion Subject: RE: How to perform a GIG MIG When we've replaced all the disks at once, we essentially did the backup-replace drives-restore routine. Everything I've heard says that a re-load not only distributes your data in the most efficient manner, but will be faster than removing disks from the config. You also end up with a known good system save or two. Our process is: 1. Make 2 GO SAVE/21s (I guess we're paranoid). We clean the tape drive before the first save and use new tapes only. 2. Remove any optical media from the CD drives. 3. Power down & remove all disks being replaced. Note that (at least on 7xx and newer) you should't need to note the exact location the old drives were in. They only need to be attached to the same controller card; the exact disk slot doesn't matter beyond that. 3. Install the new drives & IPL from D (alternate load source). This is why we remove any optical media: When IPLing from D the system might see & attempt to IPL off a CD disk before it sees the tape drive. While harmess (unless you happen to have the LIC CD loaded), it'll add time to your IPL). 4. Perform the restore as detailed in the Backup & Recovery manual. It's procedures will guide you through building the RAID set(s), adding disks to the ASP, and the restore itself. Really, all of this, including disk replacement, is in the Backup & Recovery manual. Truly the most helpful IBM manual I've ever used. For this scenario, I typically will make my saves and then follow the "load source failed, no RAID enabled" checklist which assumes the load source has failed and, since no RAID was enabled, the system has to be restored from backup. The only downside to most shops is the loss of spool files. In our shop reports are converted to PDFs in the IFS so we don't consider SPLFs to be of value. If it is an issue for you, you can acquire one of the inexpensive SPLF save applications. Or, if you've access to another box, RMTOUTQ all the SPLFs to that machine, do the upgrade, RMTOUTQ them back. I've done this 4 or 5 times over the past few years and have never had a problem. John A. Jones, CISSP Americas Information Security Officer Jones Lang LaSalle, Inc. V: +1-630-455-2787 F: +1-312-601-1782 john.jones@xxxxxxxxxx This email is for the use of the intended recipient(s) only. If you have received this email in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not keep, use, disclose, copy or distribute this email without the author's prior permission. 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