One question would be is , how does the backup to tape work at acceptable speeds when using a NBU policy in the same environment ?
Dave -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Joe Royer Sent: 10 July 2007 15:49 To: [email protected] Subject: Re: [Veritas-bu] Catalog performence to tape I have gone a few rounds with this issue myself, and here is what I learned: - Catalog disk needs read performance, not write. - RAID-5 is faster than RAID-10 for sequential reads. - If you put your catalog on SAN disk, don't use the same HBA/port that you use for tape. - Most servers' internal RAID controllers are brain dead My catalog is about 70GB and I can back it up from internal disk to LTO2 in about 50 minutes. Given what I have seen in the past, I can't complain about this number. My master is an IBM x345 with six U320 SCSI drives. Once upon a time (before me), it was configured with all six drives in a single RAID-5 and when the catalog ran the OS would suffer because it was all the same virtual disk. I had an opportunity to rebuild the box and I thought I'd be smart and change it up a bit. I made a 2-disk mirror for OS, and a 4-disk RAID-10 for the NBU catalog. This did not work well. It turns out the internal LSI RAID controller is brain dead (as are most low-end raid controllers) and was doing a round robin read on what actually appeared to be a RAID-0+1. So, my performance was actually worse than it was on a single spindle. As a temporary measure, I moved the catalog to SAN space. It screamed. SAN was the best performance I have seen out of the catalog (see two HBAs above), but I wasn't too comfortable putting my catalog on SATA disk, SAN or not, so this was just a temporary home while I converted the 4-disk "RAID-10" to RAID-5. Once this was complete, I had acceptible speeds again (above the minimum 10MB/s for my HP LTO2 drives). -- Joe Royer / SysAdmin / Digital Motorworks / 512-692-1028 This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. _______________________________________________ Veritas-bu maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu Notice to recipient: The information in this internet e-mail and any attachments is confidential and may be privileged. It is intended solely for the addressee. If you are not the intended addressee please notify the sender immediately by telephone. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to external clients any opinions or advice contained in this internet e-mail are subject to the terms and conditions expressed in any applicable governing terms of business or client engagement letter issued by the pertinent Bank of America group entity. If this email originates from the U.K. please note that Bank of America, N.A., London Branch and Banc of America Securities Limited are authorised and regulated by the Financial Services Authority. _______________________________________________ Veritas-bu maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
