Hi Bruce - >> >> Recovery at a DR site is the same thing - 9 mod-3's vs 1 27 (insert shrug >> here). >> >Maybe not. If the DR site has sufficient tape drives, you could do 9 >concurrent restores of -3s versus 1 restore of a -27. Good point - but in our case, we back using 20 streams at home and we have 20 drives available at DR. We're using 3592's; so each stream ends up on 1 tape - mostly. So it doesn't matter much to me if I restore 20 mod-7's over x hours or 180 mod-3's over the same time span.
>> As far as an onsite recovery goes in the case of a volume failure, I'll >> admit that recovering a single mod-3 would be faster than having to do any >> entire mod-27; but in the 7+ years I've been in this shop, I don't >> remember having to recover a single volume because of an actual volume >> failure. I've recovered volumes for other reasons, but generally the time >> involved there isn't concern. So of course, here I'm knocking on wood as >> I'm as superstitious as the next person. >> >If you have to recover one or a few datasets from a backup, restore from >a -27 can take longer than from a -3. Can be an issue when some >over-excited application manager is watching over your shoulder. Applications are supposed to be taking their own backups for onsite recovery. Our DR backups are headed offsite shortly after they're created. If I have to recover application datasets from a DR backup, it generally is going to involve recalling a tape from the vault 1st - which means it's generally an option of last resort and the applications know there is going to be some time involved. >> >> We did get caught short when we started as we didn't anticipate how Big we >> really needed to make the VTOC, Index, & VVDS. >What sizes did you end up with? We have found that users often greatly >oversize the VTOC, etc. We're defining the VTOC as 600 tracks and the VTOCIX as 270tracks for a mod-27 and double for a 54 - and we are probably oversizing them, but we decided we'd rather have some wasted tracks in the volume metadata as opposed to having space on the volume we can't use. I guess this all points out how much your environment affects your requirements and results. ************************************************************************************** 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
