Highlighted
Mattpstanding Absent Member.
Absent Member.
1064 views

Data Protector A6.10 and LTO 6

I have a Quantum Scaler i40 library with an Ultrium LTO 6 drive. It is connected to a Windows Server 2003 R2 with a SAS connection and if I try and backup a local drive in the server the max speed I can acheive is 8MB/s which it slower than a Windows copy/paste.

I have mad sure that the driver, library and SAS HBA are all using the latest drivers and firmware and that the drive and library are healthy. However I am unable to get a faster write time.

 

Can anyone suggest anything.

0 Likes
3 Replies
Bob_Clark Absent Member.
Absent Member.

Re: Data Protector A6.10 and LTO 6

First, according to the Device support matrix

 

http://support.openview.hp.com/selfsolve/document/KM718727/5049eb547ecf6173e77df9e0/Device_Support_Matrix_6.1x.pdf

 

this is an unsupported configuration, DP 6.10 only supports up to LTO-4.  I am not even sure if LTO-6 is supported on the latest version of DP

 

Having said that, I would look at concurrency as being a posible cause for this.  Concurrency is the number of data streams that can be written to a media at the same time

 

Modern tape drives are capable of writing much faster than most data gets sent to them, so, as a result, there is sometimes a point where the tape drive stops, and waits for the Tape buffer to fill.  When it is sufficiently filled, teh tpe has to re-position to the last file mark with some buffer characters, and starts writing to the tape again until, again, the tape buffer empties

 

To avoid this, you increase the concurrency to 10 -> 15, or even more.  This is done in the Propertis of teh tape drive in the Backup specification -> Destination tab

 

Of course, you have to have enough data stremas to make use of the concurrency.  A data stream is an Object (mounted File System), so, if you are only backing up 3 objects, you will never meet the concurrency value, and your backup will continue to be slow

 

I am going to try and attempt to attach a powerpoint presentation that illustrates this

0 Likes
Mattpstanding Absent Member.
Absent Member.

Re: Data Protector A6.10 and LTO 6

Thanks Bob,

 

I'm suprised to hear of possible library/drive compatibility issues as I was assured by the supplier that is was fully compatible:

 

http://h10032.www1.hp.com/ctg/Manual/c01631143.pdf

 

Thanks for the advice on conccurancy, I will try that this morning and will also go through the ppt you attached.

 

Thanks again,

 

Matt

0 Likes
André Beck
Visitor.

Re: Data Protector A6.10 and LTO 6

Hi Matt,

 

LTO6 is a hell of a data sink and needs powerful hardware to be driven to expected throughput (it got better rate matching than LTO5, though). Servers from the age of Win2003R2 may actually be on the brink of not being adequate, depending on the block size in use. For LTO6, I would recommend 512KiB or more, with 256KiB as the absolute minimum in case it is unavoidable for compatibility reasons. Everything smaller and a BMA may overload a CPU core before reaching a streaming rate, let alone LTO6 full blast. That's orthogonal to the need for multiplexing (or staging) as communicated by Bob, given it is hard to find sources that can conjur up data that fast, specifically from the age in question.

 

HTH,

Andre.

The opinions expressed above are the personal opinions of the authors, not of Micro Focus. By using this site, you accept the Terms of Use and Rules of Participation. Certain versions of content ("Material") accessible here may contain branding from Hewlett-Packard Company (now HP Inc.) and Hewlett Packard Enterprise Company. As of September 1, 2017, the Material is now offered by Micro Focus, a separately owned and operated company. Any reference to the HP and Hewlett Packard Enterprise/HPE marks is historical in nature, and the HP and Hewlett Packard Enterprise/HPE marks are the property of their respective owners.