July 06, 2005
Easy and Affordable Backup Optimization
By Gilles Schipper
It’s nice to be back with Ron Seybold’s 3000 NewsWire to offer some of my experiences with the HP3000, after contributing way back in the days when he edited The HP Chronicle.
When Ron called to interview me, one of his questions was “Other than finding a new machine, what's the best thing a customer can do to improve performance and reliability of their 3000 systems today?”
To me, there was a single and obvious answer – improve I/O performance.
Obvious for two reasons – because many, if not most, HP3000 systems are I/O bound (ie, I/O is the major resource bottleneck), and secondly because enhancing that resource does not affect the user licensing fees associated with many 3rd-party software licenses.
Improving I/O performance is generally associated with improving disk I/O. Disk I/O represents the very largest component of total I/O transactions generated by the HP3000.
However, without expanding upon the various options available to reduce the I/O bottleneck (which I will do in the future), let me suggest a very simple and affordable opportunity to achieve significant improvement in tape I/O performance and thus reduce your system backup times.
Shortening the time necessary to complete your backup means increasing the availability of the system for online productive use.
Other benefits could include reducing times necessary for system updates, patching, and file restoration from backup.
If you are currently using dds, dds1, dds2, or dds3 tape drives as your backup device, you could gain significant improvements in tape reading and writing times by simply replacing the drive with a dds4 – a very affordable option.
Moreover, this simple tape drive replacement requires not even a system reconfiguration and will result in immediate benefits.
There is even more good news.
This dds4 tape drive – also known as the HP Surestore DAT40 tape drive – can be used to create SLT tapes and boot from these tapes.
If your procedures include creating an integrated SLT and full backup on a single dds medium, you will be able to continue doing that.
Tape speed improvements over your existing tape drives will vary according to the drive that is being replaced, and the system that is undergoing this drive upgrade.
The slower the original drive, the more significant the improvement.
In general, the faster your system is, the more spectacular will be the improvement.
For example, expect to see as much as 67% speed reduction from upgrading your dds3 unit to a dds4 on an e3000/N4000 single CPU system.
For a 918 system, the same tape drive upgrade could see a full backup time reduction in the neighborhood of 33%.
You may have read or heard some HP3000 experts espousing the benefits of DLT over DDS technology.
To a certain extent, that may be true. DLT is said to be more reliable and faster than DDS.
That would certainly be true in comparison to DDS2 and earlier models (The DDS2 being especially unreliable in my experience).
However, the DDS4 compares quite favorably to the DLT7000 and 8000 models, both in speed and reliability.
And, unless you have an e3000 A-class or N-class, you will not be able to afford the luxury of being able to use the DLT as a boot device, and so would need to retain your DDS drive and forgo the convenience of integrating SLT and backup on the same medium.
Although I have not tried one, I would suspect that the even faster DDS5 drive (also referred to as DAT72) would also work very nicely on the HP3000
It seems that after many pundits were announcing the death of DDS technology, it has seen a remarkable rebirth.
You just need to visit www.datmgm.com to gain an illuminating peek into the bright future of DDS technology.
And for those of you wondering, no I do not have any financial interest in DDS technology.
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Typo in original post regarding web site for more information about dds technology.
Should be www.datmgm.com.
Posted by: Gilles Schipper | Jul 6, 2005 8:46:30 AM
I believe that the DDS4 drive will not read a 60M DDS1 tape. So you will need to think about archived tapes that you may need to read and vendors need to make sure that they are using at least DDS2 tapes.
And the DDS5 won't handle DDS2 tapes.
Things to keep in mind.
Posted by: Gary Jackson | Jul 7, 2005 12:12:56 PM
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