I did a restore of our database last Monday. It took about 5.5 hours for 60G with nothing else running on the server, with an LTO-1 tape drive, SCSI attached, to our IBM 3583 library. This is in a Windows2000 environment, but even at that, this is VERY slow. The daily full backup of the database seems to take the same amount of time.
I would like for the database restore to be faster, but the backup is a problem too. I would like to know how to make a database backup to a remote DISK drive (or a TSM-DR system) and how to restore the database on that system from that disk drive file! (Pointers to admin docs would be fine! :) ) -----Original Message----- From: Tab Trepagnier [mailto:[EMAIL PROTECTED] Sent: Friday, January 21, 2005 5:16 PM To: [email protected] Subject: Re: Why do database restores take so long? Dave, Our database disk system consists of four 18 GB SCSI disks in a split (dual-bus) disk pod connected to a dual-channel LVDS adapter. The Recovery Log in on another pair of such disks. One set of disks on one bus holds the primary database and log volumes; two DB and one log disk. Each DB/log volume is mirrored to an identical volume/disk on the other bus. So the mirror read/writes occur on independent buses downstream of the PCI slot. The database consists of four volumes per disk of about 4 GB each. All database and log volumes are defined on JFS2 file systems. The LVDS adapter is the IBM 64-bit dual-channel adapter called "PCI DUAL CHANNEL ULTRA3 SCSI ADAPTER", Part Number 09P2544. The disks are "16 Bit LVD SCSI Disk Drive (18200 MB)", Machine Type and Model = ST318305LC which I *think* is 15K rpm. The server is a 2-way 6H1 64-bit 600 MHz with 4 GB RAM, tuned for just about zero paging. TSM DB buffer pool is 1 GB. Like I said, when backing up to our HP 4/40 DLT via HVD SCSI, topas reports a consistent 11 MB/s, such that a typical backup takes just about 45-50 minutes including the tape mount. The restore took slightly over three hours; and the 3:1 ratio is not out of line based on other responses. Thanks. Tab "ADSM: Dist Stor Manager" <[email protected]> wrote on 01/20/2005 11:27:02 PM: > Can you provide a little more information? I would like to know: > > 1. What kind of disk subsystem are you restoring the data to? > 2. How many disks, and what kind of disks are they? > 3. How is the database laid out database volume wise? > 4. Does the disk have write cache behind it? > 5. What kind of controller do you have for the disk subsystem? > > At 07:23 PM 1/20/2005 -0600, you wrote: > >TSM 5.1.9.0 on AIX 5.2 ML4; DLT8000 media on SCSI > > > >Why do TSM database restores take so much longer than the backups? Our > >system backs up our 24 GB database to DLT in about 50 minutes with a > >sustained rate of 11 MB/s reported by topas. > > > >Tonight I'm performing a database restore. It is occurring at an average > >rate of less than 1 MB/s with rare peaks no higher than 6 MBs. At times > >the rate is as low as 300 KB/s. > > > >I realize the system is writing data to disk rather than reading so its > >not doing as much caching, but these are new disks and I've seen them > >stream write at better than 25 MB/s on the inner edge and as fast as 50 > >MB/s on the outer edge. So I doubt the disk is the problem. > > > >This restore has been running for almost 2-1/2 hours now and is about 90% > >complete. > > > >This is the fourth or fifth time I've restored the TSM database in the > >seven years I've operated the system. I have never seen database restores > >exceed 1/3 the backup rate - sustained - on two different servers, three > >different media and going back to ADSM 3.1. > > > >Just curious. > > > >Tab Trepagnier > >TSM Administrator > >Laitram, L.L.C. > > Dave Canan > TSM Performance > IBM Advanced Technical Support > [EMAIL PROTECTED]
