Super DLT Tape Drives

[bommer]

We are considering replacing our DLT7000 tape drives with the new Quantum super DLT's. Is anyone using these with Legato? We have a STK 9710 silo using Networker 6.0.2 for HP-UX. They are on the compatibility list but I'd like to get some real confirmation they work at the advertised speeds (11MB per second).

 

[Sunboxez]

We're using LTO with our STK which claim 15mb/s uncomp. native transfer rate. I can't vouch for SDLT, but seeing as they're direct competitors it should be close. Our server is also the storage node so it can bypass TCP/IP overhead for backups so we get 14 mb/s for the server with parallelism=4. Clients are a different issue. Your drives should be able to do 11/22 uncomp./comp but the real bottleneck is your network. Keeping 4 SDLT drives streaming at max sustained transfer would require 40 mbytes/s avail bandwidth. Assuming you're servers on a fast-E switch your max throughput will be 10-12 mbytes/s (from 100 mbits/s) total so if you get 4 SDLT drives streaming, they will split you total available bandwidth so you won't see the numbers you expect. Now if you're on fiber and can support higher speeds you should see those drives stream at spec and burst even higher. BTW what speeds do you avg with DLT7K drives now? If you not seeing 8-11mbytes/s compressed now you might simply want to performance tune.

 

[bommer]

We do have a fiber connection from the network to our Networker host server We are getting 5 to 8 mb per second with higher bursts from clients that can push the data. We're still considering a beefier host server and/or a second fiber channel from the network to feed these drives among other things.