Thanks for the advice, everyone. I did neglect to mention my tape
hardware. I have a Spectra Logic 20K library with 8 AIT-3 tape drives
(100/260 GB, 42GB/hr). But until I have some real compression and job
length statistics to work with, I won't know anything. So for now I'll
take the hit then do some analysis.
Thanks again,
Justin
jwalton AT securecomputing DOT com wrote:
> In my experience, you gain a 14% increase in capacity by using the
> non-compression device on highly compressed (i.e. gzip) data. However, I
> just chose to take the capacity hit rather than do something like Justin
> proposes. Therefore my DLT8000 tapes were maxing out at 34G-35G instead
> of the native 40G. Other drive types might be different though.
>
> -Jon
>
> On Wed, 21 Jan 2004, Rockey Reed wrote:
>
>
>>Justin,
>>
>>Don't mess with turning the compression off on the tape drive. If the data
>>is already compressed the tape drive will not affect it. You gain nothing
>>and make management a nightmare if you try to work with compression on/off
>>depending on the backup policy. However, if you insist on doing a bn/cbn
>>configuration, I recommend having two or more drives and configure one
>>without compression, put it in a separate storage unit and use that STU for
>>the backup of the file system.
>>
>>HTH,
>>Rockey
>>
>>-----Original Message-----
>>From: veritas-bu-admin AT mailman.eng.auburn DOT edu
>>[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]
>>Sent: Wednesday, January 21, 2004 1:29 PM
>>To: veritas-bu AT mailman.eng.auburn DOT edu
>>Subject: [Veritas-bu] Changing tape drive paths
>>
>>I am just now setting up a backup system using NBU 4.5MP6 on a Sun
>>Enterprise 5500 server running Solaris 9.
>>
>>Most of the data I will be backing up is typical Unix and Windows stuff,
>>plus some Oracle databases. However, on my SAN I have a 6 TB filesystem
>>that will eventually be about 95% full. The vast majority of that data will
>>already be compressed (using a proprietary format), so I would not want to
>>use the hardware compression device. But for everything else (presumably) I
>>would want to use compression.
>>
>>The only way I can think to handle this is to use, for example,
>>
>> tpconfig -update -drive 0 -path /dev/rmt/0bn
>>
>>in a notify script (maybe session_start_notify) and then
>>
>> tpconfig -update -drive 0 -path /dev/rmt/0cbn
>>
>>in the corresponding end script (session_notify). If I were to do this, I
>>know I would need to make sure that the 6 TB filesystem is the only one that
>>would run in the session.
>>
>>Does anyone have experience with this sort of a situation, or am I just
>>overlooking a better method of handling this?
>>
>>Thanks,
>>
>>Justin
>>
>>
>>--
>>Justin C. Lloyd
>>Unix System Administrator
>>MCI System Technology Solutions
>>Office 703.886.3219 Vnet 806.3219 Fax 703.886.0132
>>
>>_______________________________________________
>>Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
>>http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>>_______________________________________________
>>Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
>>http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>>
>
>
--
Justin C. Lloyd
Unix System Administrator
MCI System Technology Solutions
Office 703.886.3219 Vnet 806.3219 Fax 703.886.0132
|
