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MSL6060 - Checking if compression is on.

Mark Bly
Regular Advisor

MSL6060 - Checking if compression is on.

We have a MSL6060 with 4 Ultrium 460 drives.

When I was looking at the Web interface I noticed that in the status screen the drives are showing as: Compression On? NO

I went to the setup screen and entered the drive configuration area.
Here there is a column for Data Compressing but when you change it to ON and click on Submit it does not seem to change the details in the status screen.

Are we running without hardware compression on or is the status screen reporting incorrectly?

Re-entering the Drive configuration screen shows the compression drop down list as OFF again.


Mark
Remember to think before you react................but always make sure there is still time to react
18 REPLIES
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

My guess is that the status screen is incorrect. I'll investigate and let you know.

What version of library code do you have?
The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

Hi David,

Thanks for your reply.

The details are as follows:

Library
Firmware Revision: 4.14
Hardware Revision: 3
Boot Version: 3

Drives
Product ID: Ultrium 2-SCSI
Product Revision Level: F38W
Firmware Revision Level: 006.505

This is a new library which we are still performance testing. We did notice that the best throughput achieved so far was approx. 12Mb/S (which we consider to be very poor for Ultriums)
This performance could be due to the data that we are backing up.

I tried connecting to the Library using the serial cable supplied but could not get a telnet session to work (Also tried the MSLUtil.exe utility through the serial connection but it would not connect)

How can we guarentee that compression is on?


Mark
Remember to think before you react................but always make sure there is still time to react
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

Mark,

Now would be a good time to update to 4.23 library firmware. The drive firmware is up to date.

You shouldn't need to use MSLUTIL. The diagnostic tool of choice is HP L&TT.

Regarding the compression status, we'll investigate this to see if the GUI is reporting it correctly.

In the mean time, you can view the support ticket (in L&TT0 for the drive to check The data compresson statistics. The one trick is you need to view them before the tape is unloaded (and they are cleared).

Regarding performance, there are device and system performance tests in L&TT that can help you figure out where the bottleneck is.

The journey IS the reward.
Wojciech Kozikowski
Occasional Contributor

Re: MSL6060 - Checking if compression is on.

BTW, some days ago I saw F43W (006.942)
drive firmware version for LTO2 drives installed in MSL6060.

Regards,
Wojtek
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

Yeah, your right - we have updated LTO2 firmware out there as well (F43W for the MSL/ESL).

In LTT 'Get files from web' you can use the 'details' button to see the change list for both 4.23 and F43W.
The journey IS the reward.
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

Mark,

> When I was looking at the Web interface I noticed that in the status screen the drives are showing as: Compression On? NO

> I went to the setup screen and entered the drive configuration area.
Here there is a column for Data Compressing but when you change it to ON and click on Submit it does not seem to change the details in the status screen.

Are you viewing/changing this with a tape loaded or not? Some drives don't allow changing of compression (and don't report compression enabled) when no tape is loaded. I'm not sure if that's the case with LTO2.
The journey IS the reward.
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

I tried an MSL6000/LTO2 with 4.23 firmware. What I found is the status always says "Yes" for compression, with or without a tape. When I attempted to change it from the Setup page, I could change it to "No", but it would still say "Yes" when I went back to the main status page.

The results were the same with or without a tape loaded.

So, I seem to have different results than you have.

Are you on a windows/HP-UX/RH host? If so, can you install HP Library & Tape Tools? You can the use the support ticket to view the compression logs after a backup (but the tape must still be loaded).
The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

David,

I installed the L&TT software but it does not appear to work (Version 3.4)

After trying to scan for the devices the following message appears:
-----------------------------------------
There was a problem scanning this system that may or may not effect tool usage.
Press any key to continue.
-----------------------------------------

It then goes on with the following:
-----------------------------------------
Building Device Map
Checking for redundant devices.
Searching for drives of Library 'HP MSL6000 Series' at address '8.0.0[0-0/1...
-----------------------------------------

After failing to find the devices with the first two methods it finally finds 2 of the 4 drives by serial number. This is expected as this test machine is only plugged into one Brocade switch (same as drive 1 and 2 along with the Library controller)

When I hit any key to list the command options and then choose options from the menu, the following appears with no choices:
-----------------------------------------
Scan Details > Options >
List of all valid options (Scan):
Type the corresponding number to select or deselect each option
-----------------------------------------

What am I doing wrong?


Mark


Remember to think before you react................but always make sure there is still time to react
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

>-----------------------------------------
>Scan Details > Options >
>List of all valid options (Scan):
>-----------------------------------------

>What am I doing wrong?

Nothing :-)

When there are errors during the scan, it puts you into the 'scan detail' submenu (so you can see what went wrong). Use "up" to get back to the main menu, and then you should have a selectable device list.

Type ? to see the commands available in each menu screen.

Out of curiosity, are you on HPUX, RedHat, or Netware?


The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

David,

Typing 'up' took us to the correct screen.

We thought that the first screen that appeared was the top level.

The system that we are using for the tests is running HP-UX 11i.
The library is connected to the SAN via a Brocade switch.

I am a bit worried that L&TT picked up the controllers on our XP512. Can it cause any problems?


Many thanks for all your help.


Mark


Remember to think before you react................but always make sure there is still time to react
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

> I am a bit worried that L&TT picked up the controllers on our XP512. Can it cause any problems?

LTT parses the kernel version of the ioscan (i.e. it doesn't rescan the system), and looks for SCSI/FC devices that it supports. It lists the 'other devices' it finds, but you cannot select them.

When it finds a tape library, it uses the SCSI read element status information to associate any drives on the system with the correct library.
The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

David,

Sorry to return to a previous thread but we have just carried out our first proper full weekly backup using the tape library.

We used one of the Ultrium 460 drives and backed up one of our development systems.

System:
HP-UX 11i attached to XP512

Total Data backed up:
262.41 GB

Length of backup:
8 hours 17 minutes

No of Media used:
2

Backup software:
Omniback 4.1 with drive concurrency set to 5

Media:
HP Ultrium 2 tapes

As you can see we went onto two tapes. This happened at about 170GB.

I thought that Ultrium 2 tapes had a native capacity of at least 200GB. Surely we should have been expecting well over 300GB per tape (obviously not expecting the 2:1 compression capacity of 400GB)

This would seem poor for an Ultrium 1 drive with compression let alone an Ultrium 2 drive.

What tool should I use from L&TT to figure out what is going on? It looks as if something is wrong with the library or drives.

Mark
Remember to think before you react................but always make sure there is still time to react
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

Mark,

Can you collect a LTT support ticket (select Support tool, select save to file) after the backup?

You can copy the support ticket to a windows host, and then view it with the windows version of LTT.

There is a data compression log which will show the MB from the host, and MB written to the tape.

I believe the log is cleared on a tape load, show it should represent one tape worth of data. On DLT drives the log is cleared on a tape unload, you you need to grab it before the tape is unloaded. I don't know if LTO is the same, or if it's still available after the tape is unloaded (I'll try it when I'm back in the office).

This log will show us if compression was enabled, what the compression ratio was, and how much data went on tape.
The journey IS the reward.
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

> Total Data backed up:
> 262.41 GB

> Length of backup:
> 8 hours 17 minutes

That's only 8.8MB/sec (including the time to swap tapes). The lowest streaming rate of the drive is 10MB/sec (native)

Were you just backing up to 1 drive at a time?

You might want to try the device performance tests to make sure the drive can stream. These are included in LTT, or available as separate utilities (hptapeperf). See this page for more info:
http://www.hp.com/support/pat
The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

David,

I just tried to run a support ticket against the drive using L&TT.
If I try to start the L&TT software with a backup running it does not detect the drive.

How can I keep the tape in the drive after a backup to get the compression report? (The library will automatically eject the tape when using omniback)

L&TT is definitely identifying these drives as Ultrium 2 but the performance still seems to be that of an Ultrium 1 (capacity of Ultrium 2 tape is less than 200GB)


Mark
Remember to think before you react................but always make sure there is still time to react
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

> I just tried to run a support ticket against the drive using L&TT.
If I try to start the L&TT software with a backup running it does not detect the drive.

In general, that's a limitation of in-band diagnostics through the OS. There's a workaround on windows (use the ASPI I/O option), but not on HP-UX.

> How can I keep the tape in the drive after a backup to get the compression report? (The library will automatically eject the tape when using omniback)

Yes, I realize there's a catch 22 here. I ran some tests over the weekend (on windows) to determine when the compression logs get cleared, but I haven't had time to look at the support tickets yet. Hopefully I'll get to that this evening.

The journey IS the reward.
David Ruska
Honored Contributor

Re: MSL6060 - Checking if compression is on.

> I ran some tests over the weekend (on windows) to determine when the compression logs get cleared...

It looks like the data compression log gets cleared as soon as the tape is unloaded (I was afraid of that).

I don't have a good answer on how to collect the compression information in a library drive. I will have to speak with a few folks and see if they have any brighter ideas.
The journey IS the reward.
Mark Bly
Regular Advisor

Re: MSL6060 - Checking if compression is on.

Closing old thread
Remember to think before you react................but always make sure there is still time to react