Hi all, just like to paraphase, ...  "I WANT my DLT!"
John "Will this backup never end" Skelton

Date:          Fri, 18 Oct 1996 08:13:20 PDT
Reply-to:      Mark Klein <[log in to unmask]>
From:          Mark Klein <[log in to unmask]>
Subject:       Re[2]: DLT and HP3000's - they do co-exist
To:            [log in to unmask]

Neil comments in response to Lee's performance numbers with DLT:

>Lee observed......

[and I trimmed]

>>
>>For anyone who's interested in using DLT on the HP3000:
>>
>>In the latter case, we set up our full system backup one
>>evening to use the DLTs in parallel, and the backup took
>>4.75 hours and consumed 2 DLT cartridges .... Our current
>>backup ... takes approximately 8 hours ...
>

To which Neil responded:

>They backup about 22GB in about 90 minutes (1h30) onto four 120m DAT
>cartridges.

>So by extrapolation, 88GB would take 6Hrs to four drives (4 x 1h30),
>but would have to be attended to perform a DAT swap, and maybe only 3
>hours to eight drives in parallel, unattended. Or even 4h30 to 6 drives
>also unattended since 88GB / 6 = 14.6 GB per DAT.

>I'd be looking for a quantum leap in backup technology, say like the
>difference between the old Cartridge and the 7980XC before recommending
>a shift away from DDS. Maybe we'll get solid state backups in five
>years - or liquid memory :)

and I'll continue with a <plug alert>:

We have a customer that is using DLT in production with Backup+ and has
balanced his devices across multiple SCSI channels such that the bus
contention noted in Lee's case is not present. With that in mind, he is
seeing 20Gb per hour to the single drive. In Lee's original post, he
states that the drives shared the same channels as the disks. Still a
very good performance figure considering no balancing. So, with multiple
drives, it is entirely possible that Lee's 88Gb could be backed up in
slightly over an hour, completely unattended. Now when you consider
these performance numbers with Delta Backup, I would say there is a
significant leap in backup technology.

Check out http://www.orbitsw.com for our white papers on DLT.

</plug alert>