>>Can you describe this backup process a little? E.g., I assume you use some >>kind of FlashCopy. If so, then you need 4,000 more addresses for their
>>secondary volumes, right? How much total elapsed time does it take to do all >>those backups? How many output tapes are produced? What DASD vendor? If you >>start all 4,000 FlashCopies at once, how long does that take? Total down time >>for the backup site before you start mirroring again? How long to get back >>in sync? >>This sounds like the kernel of a good session for SHARE or CMG. >>Bill Fairchild >>Rocket Software Bill - because you asked - We have a DS8100-931 from IBM defined with a total of 6576 online devices (mixed mod-3?s, 9?s, & 27?s). Approximately 4400 volumes are currently in use. To support this configuration, our DS8100 has 28 LSS's/Arrays and 44 LCU's online and a matching 44 offline. We describe the online devices as being the front half and the offline devices as being the back half. All of our online devices are in a one to one relationship with the corresponding offline device, i.e. address 5000 is always paired with offline address 9000. We backup approximately 4400 volumes on a daily basis to 3592 tapes which fits onto 20 3592 300GB cartridges. Our backup cycle runs in approximately 4 hrs. We could actually use less than 20 cartridges but choose to use 20 drives for backups as we have 20 drives at the DR site available for restores. We established a PPRC Metro Mirror - Loop Back environment, which means that we PPRC from the front end of the box to the back half of the box. We were told that in a metro mirror with 30 kilometer separation in full Synchronous mode, the delay could be up to .08 ms on writes. Since our loop back metro mirror is approximately 3ft, our delay is less than .03 ms. on writes. We run in synchronous mode from 16:00 to 03:58, at 03:58 we still do our DB2 and IMS log suspend as soon as this happens we issue a freeze against all of the LSS's this process takes roughly .3seconds. A freeze breaks the relationship between your PPRC primary and secondary volumes. We then do a failover which is a series of ICKDSF commands to prepare the PPRC secondary volumes to be backed up. We backup the offline volumes (our PPRC secondary devices) using Innovations FDR products. The backups themselves take 4 hrs. Once the backups complete, we re-establish the PPRC pairs, do a failback, and sync up in XD mode (extended distance). We currently wait until 16:00 to issue the commands to go fully synchronous. Which has more to do with a application tuning problem than any performance issues with PPRC. Resuming in XD mode takes about 45 minutes - times vary depending upon how many writes were executed during the backup window. A query job run prior to going to XD mode will show exactly how tracks are out of sync. We have three jobs that run single thread to convert us to from XD mode to syncronous mode. Each job runs about five minutes. As a note, the 1st time we established the PPRC pairs, we ran it on the weekend and it took 13+hours. ************************************************************************************** This e-mail message and all attachments transmitted with it may contain legally privileged and/or confidential information intended solely for the use of the addressee(s). If the reader of this message is not the intended recipient, you are hereby notified that any reading, dissemination, distribution, copying, forwarding or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately and delete this message and all copies and backups thereof. Thank you. ************************************************************************************** ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
