Date: Tue, 24 Aug 2004 13:08:08 -0500 From: Dan Rue <drue@therub.org> To: Odhiambo Washington <wash@wananchi.com>, freebsd-questions@freebsd.org Subject: Re: SCSI disk to disk dump restore Message-ID: <20040824180808.GN68870@therub.org> In-Reply-To: <20040824081210.GI41956@ns2.wananchi.com> References: <20040823210023.GJ68870@therub.org> <20040824081210.GI41956@ns2.wananchi.com>
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On Tue, Aug 24, 2004 at 11:12:10AM +0300, Odhiambo Washington wrote: > * Dan Rue <drue@therub.org> [20040824 00:01]: wrote: > > Hey Gang, > > > > I had an older scsi disk going bad, so I picked up a new disk to replace > > it. I did a dump | restore to move the data to the new disk, but it > > went far slower than expected. I'm wondering if there's an issue with > > the different disk speeds. > > > > Old disk from dmesg: > > da0: <QUANTUM ATLAS IV 18 WLS 0808> Fixed Direct Access SCSI-3 device > > da0: 80.000MB/s transfers (40.000MHz, offset 31, 16bit), Tagged Queueing Enabled > > da0: 17522MB (35885168 512 byte sectors: 255H 63S/T 2233C) > > > > New disk, as reported by dmesg (it's a seagate U320): > > da2: <SEAGATE ST336607LW 0007> Fixed Direct Access SCSI-3 device > > da2: 80.000MB/s transfers (40.000MHz, offset 63, 16bit), Tagged Queueing Enabled > > da2: 35003MB (71687372 512 byte sectors: 255H 63S/T 4462C) > > > > The dump was 13G, and took about 2 hours. I calculated that out to be > > about 1.8MB/s. Of course, that's total time I'm sure there's some dump > > overhead (though, i didn't use -L) - but still, 2 hours for 13G?! > > Well, depends! I used a dump|restore (without -L) recently and it took > me like 5 hours to complete the dump for 28GB. > > > > I'm thinking there was a jumper or parameter I should have set due to > > the different disk types. Note that I removed da0, but there's still > > another quantum in the machine on the scsi chain. > > I also had another disk on the SCSI chain. > > How much time did you expect to achieve as optimum? Based on what > factors? Ok, well that's good enough for me. I don't have a lot of experience with SCSI or dump - so I thought maybe I was hitting some caveat, especially with the mixed drive types. Thanks for the info it sounds like my numbers were about right after all. drue
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