cancel
Showing results for 
Search instead for 
Did you mean: 

Transfer Rate

Ayman Altounji
Valued Contributor

Transfer Rate

He, doing a eval of SDLT getting 195 Gig on a tape at 200Meg/Min. That's slow according to the specs on this drive. Anyone else have info on these drives.
4 REPLIES
Ayman Altounji
Valued Contributor

Re: Transfer Rate

SDLT
Ayman Altounji
Valued Contributor

Re: Transfer Rate

What's the hosts config with backup SW? Sorry if this sounds dumb, but are you using hardware or software compression? I found it best to nail the tape drives H/W compression via drive jumpers or dip switches. The 11MB/sec is probably using Veritas. How's it run with NT backup?
Shot in the dark, but you could go realtime priority on the process. I've heard some vendors do it to skew the benchmarks. The capacity sounds good. My Notes DBs are natively compressed. Don't yield much on the compression levels.
Ayman Altounji
Valued Contributor

Re: Transfer Rate

OK, to start with some spews, salt native speed is 11mb/I with a 2:1 compression it will be 22mb, but only with compression. if the backup is taken from the network , 10mbit will make 875kb/I with 30% overhead ,
100mbit will make 8.75mb/I with 30% overhead . now knowing these things, you will see, it might not be the salt being the problem, but perhaps your network or even your hard drives, and probably they are, to get performance out of Ben dot, you must keep the drive in streaming mode, otherwise it goes into start/stop mode and has to reposition to th e last inter record gap on the tape. this will hamper you performance dramaticly.

hope to have helped you ,

ronald hendriks primairy / secondary storage trainer Compaq etec

btw, a database compresses to 1.6 : 1 on average using the agent for the backup application [ also for open files ]
Ayman Altounji
Valued Contributor

Re: Transfer Rate

OK, to start with some specs, sdlt native speed is 11mb/s with a 2:1 compression it will be 22mb, but only with compression. if the backup is taken from the network , 10mbit will make 875kb/s with 30% overhead , 100mbit will make 8.75mb/s with 30% overhead . now knowing these things, you will see, it might not be the sdlt being the problem, but perhaps your network or even your hard drives, and probably they are, to get performance out of the sdlt , you must keep the drive in streaming mode, otherwise it goes into start/stop mode and has to reposition to the last inter record gap on the tape. this will hamper you performance dramaticly.
hope to have helped you ,

ronald hendriks primairy / secondary storage trainer Compaq etec

btw, a database compresses to 1.6 : 1 on average using the agent for the backup application [ also for open files ]