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LTO4 Best Practices

Ralphus
Level 3
Partner

‎02-07-2008 07:29 AM

Hi All,

I'm lucky enough to have a lab environment where I can play with technology and create best practices for my company.   My current interest is LTO4 and NBU 6.X and I'm trying to establish key differentials between LTO3 that administrators should be aware of in terms of compatability and performance.   I'd appreciate any of your comments and experience.

1)  Solaris OS Support:  The NBU 6.X Unix Configuration Guide seems to have dropped support for non st device drivers (ie.. you can no longer use IBM's own tape driver, you must use Solaris st).  Solaris st support was included in Solaris 10 release 8/07 (http://docs.sun.com/app/docs/doc/817-0547/getjd).  Does this effectively mean that any Solaris media servers that would like to use IBM's LTO4 drive will need to run Solaris 10?  Or perhaps I've got the st requirement wrong?

2)  NBU Detection & Configuration:  From what I've read I need a new external_types.txt file as indicated by docid 293476 to ensure everything is detected OK.  In terms of tape support, there is no HCART4 type, but apparantly I can use HCART (assuming there's no LTO1 in the env..and I doubt there would be) instead w/o any problems.

3)  BUFFERS:  My own testing of backing up local SAN drives from the media server direct to LTO4 is showing that my best SIZE_DATA_BUFFERS value is 1MB (1048576).  Has anyone else confirm or deny this?   My test results are shown below:
SIZE_DATA_BUFFERS   LTO4 Throughput
128K                                   56.2 MB/s
256K                                   77.0 MB/s
512K                                   96.4 MB/s
1024K                                  106.0 MB/s
2048K                                  106.0 MB/s

4)  SOLARIS 10 /etc/system:  The Performance Tuning Guide mentions that many parameters for older Solaris systems do not apply to Solaris 10.   Does anyone have a recommended list of variables and their parameters?

For reference my test system is as follows:
Media Server is a Sun V245, 8GB, 2 x 4Gb HBAs (1 disk, 1 tape)
NBU 6.5, Solaris 10


Thanks!
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5 REPLIES 5

Darren_Dunham
Level 6

‎02-07-2008 09:55 AM


@Ralphus wrote:

1)  Solaris OS Support:  The NBU 6.X Unix Configuration Guide seems to have dropped support for non st device drivers (ie.. you can no longer use IBM's own tape driver, you must use Solaris st).  Solaris st support was included in Solaris 10 release 8/07 (http://docs.sun.com/app/docs/doc/817-0547/getjd).  Does this effectively mean that any Solaris media servers that would like to use IBM's LTO4 drive will need to run Solaris 10?  Or perhaps I've got the st requirement wrong?
Usually drive support is available for older systems via patches.  You could also just populate the st.conf file with the appropriate settings as well.

2)  NBU Detection & Configuration:  From what I've read I need a new external_types.txt file as indicated by docid 293476 to ensure everything is detected OK.  In terms of tape support, there is no HCART4 type, but apparantly I can use HCART (assuming there's no LTO1 in the env..and I doubt there would be) instead w/o any problems.
Right.  HCART, HCART2, etc... do not correspond to particular drive types.  They're purely organizational labels for you to use.  While most organizations find it easiest to map HCART->LTO1, and so on, that's not a functional requirement.

4)  SOLARIS 10 /etc/system:  The Performance Tuning Guide mentions that many parameters for older Solaris systems do not apply to Solaris 10.   Does anyone have a recommended list of variables and their parameters?
Solaris 10 raised the defaults for shared memory and similar settings.  I cannot confirm, but several reports suggest that you won't need to raise anything above the defaults.

--
Darren
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Ralphus
Level 3
Partner

‎02-07-2008 10:18 AM

Usually drive support is available for older systems via patches.  You could also just populate the st.conf file with the appropriate settings as well.

Good ideas.  Any idea where I could find the correct st.conf entries and/or the patch revisions for older versions of Solaris?  I've been through the Sun site but haven't turned up much.
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Stafford
Level 4

‎02-07-2008 02:32 PM

We recently upgraded the LTO3's in our i2k and i500 to LTO4's including the native encryption/QEKM.  Unfortunately most of our environment is too slow to even take advantage of LTO3's so I can't speak on performance tweaking yet (couple T5220's going into prod soon).  Highly interested in any tweaking others can offer.

The Solaris patch you mentioned was required to get the drives recognized properly, you might be able to do it another way but it's specifically in the release notes that it provides LTO4 support and I would just install it on all of your media servers.  We found out the hard way as we were installing the drives that the patch was required and it was a scramble to get it in.  Luckily we started with a small remote site with a single media server so it wasn't an issue to bounce it at the time.

I was able to successfully get the LTO4 drives in and working without the mappings file you mentioned, however, it did specifically mention the i500 so I went back after the fact and put it in.  I haven't noticed anything different but it's a simple change.  As others mentioned, there is no hcart4 (yet).  Hcart or whatever is logically convenient will work just fine.
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Darren_Dunham
Level 6

‎02-07-2008 02:56 PM


@Ralphus wrote:

Good ideas.  Any idea where I could find the correct st.conf entries and/or the patch revisions for older versions of Solaris?  I've been through the Sun site but haven't turned up much.
You generally just want the latest "st" patch for whatever version you are running.  That brings it up to date.

The opensolaris source code has the entries for the LTO4, but it's not in st.conf file format. 

The code shows an options field of 0x1018619, and density settings: 0x44, 0x44, 0x46, 0x46.  (And I think all LTOs should have a type of 0x3b).

--
Darren
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Ralphus
Level 3
Partner

‎02-09-2008 04:57 PM

Thanks for pointing out that the latest st patchesfor Solaris 8 & 9 would have the LTO4 drivers in them.  You were correct.   I've provided links to the patches below:

Solaris 9 st patch: 113277-58
URL:  http://sunsolve1.sun.com/search/document.do?assetkey=1-21-113277-58-1

Solaris 8 st patch:  108725-27
http://sunsolve1.sun.com/search/advsearch.do?collection=PATCH&type=collections&max=50&language=en&queryKey5=108725&toDocument=yes

I think I can now safely say that LTO4 is supported on Solaris 8,9 & 10.
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