Hi,

We've just upgraded from six HP LTO1 tape drives in Dell PowerVault
136T library to six IBM LTO2 drives.  The library is directly (SCSI, 2
channels, 39160) attached to a backup server, running BackupExec 9.0,
W2K.  The native/compressed rated speed for LTO1 is 15/30 MB/s, or
900/1800 MB/min.  Ran tests on large very compressible files with LTO1
tape drives, and got the maximum compressed speed on these tests (1800
MB/min, backing up files from local, directly (fiber - 2 HBA's)
attached storage).

LTO2's native/compressed speed is 35/70 MB/s, or 2100/4200 MB/min.
Tested backing up same set of large compressible files, and got about
2200 MB/min, which is pretty much the same as native speed without
compression.  The server is pretty fast, two 1.6 GHz Xeon processors,
4 MB RAM, HBA's are 2 Gbps, storage is 2 Gbps Clarion with FC 15rmp
drives.

Hardware compression in enabled in BackupExec on all drives...

Has anyone had any experience using LTO2, any luck getting closer to
the maximum speed, are there any known issues / limitations, any
ideas?

Thanks,

El

[ Post a follow-up to this message ]

"ELD" <eld9876@yahoo.com> wrote in message
news:60e2992e.0407270820.1bc88620@posting.google.com...
> Hi,
>
> We've just upgraded from six HP LTO1 tape drives in Dell PowerVault
> 136T library to six IBM LTO2 drives.  The library is directly (SCSI, 2
> channels, 39160) attached to a backup server, running BackupExec 9.0,
> W2K.  The native/compressed rated speed for LTO1 is 15/30 MB/s, or
> 900/1800 MB/min.  Ran tests on large very compressible files with LTO1
> tape drives, and got the maximum compressed speed on these tests (1800
> MB/min, backing up files from local, directly (fiber - 2 HBA's)
> attached storage).
>
> LTO2's native/compressed speed is 35/70 MB/s, or 2100/4200 MB/min.
> Tested backing up same set of large compressible files, and got about
> 2200 MB/min, which is pretty much the same as native speed without
> compression.  The server is pretty fast, two 1.6 GHz Xeon processors,
> 4 MB RAM, HBA's are 2 Gbps, storage is 2 Gbps Clarion with FC 15rmp
> drives.
>
> hardware compression in enabled in BackupExec on all drives...
>
> Has anyone had any experience using LTO2, any luck getting closer to
> the maximum speed, are there any known issues / limitations, any
> ideas?
>
> Thanks,
>
> El

Some thoughts: were you using LTO2 cartridges? Are the drivers recent? Also,
no matter how fast it may be,   it's worth checking with Iometer if  the
server can sustain that rate. 64K sequential reads is a good starting point.

Good luck

Art

[ Post a follow-up to this message ]

"ELD" <eld9876@yahoo.com> wrote in message
news:60e2992e.0407270820.1bc88620@posting.google.com...
> Hi,
>
> We've just upgraded from six HP LTO1 tape drives in Dell PowerVault
> 136T library to six IBM LTO2 drives.  The library is directly (SCSI, 2
> channels, 39160) attached to a backup server, running BackupExec 9.0,
> W2K.  The native/compressed rated speed for LTO1 is 15/30 MB/s, or
> 900/1800 MB/min.  Ran tests on large very compressible files with LTO1
[snip]
>
> Has anyone had any experience using LTO2, any luck getting closer to
> the maximum speed, are there any known issues / limitations, any
> ideas?
>

I'm using LTO2 just recently installed with Legato Networker.
Connected to a HP 4 CPU 3Ghz Xeon.
I'm getting up to around 35MB/s peaks with an average of 24MB/s
I did have a problem once where the speed went down to 2.2MB/s until I
rebooted the entire system.
The HP is running win2003 and this can have a problem with rebooting of tape
power whilst the main system is on. So always reboot the win2003 system
aswell.

As mentioned in the other post. Use quality LTO2 tapes only.

[ Post a follow-up to this message ]