LTO4 drive tempature - Operating temperature?

[Glen A. Harris]

We have an MSL4048 (two LTO4 drives). at idle, Drive 1 has an internal temperature of 30.0 C and Drive 2 is 33.0 C. The Library's overall internal temp is 39.1 C. The drive status shows "Internal Drive Temperature (normal range: 15 C - 67 C)", but LTO4 specs show "Operating: 50° F to 95° F (10° C to 40° C) at a minimum of 6CFM airflow. Will teh real operating temperature range please stand up?

[Richard Bickers]

Yes, that's a bit confusing... It depends where you measure the temperature as to what's expected. The internal temperature will be higher than the external one (which is what those two ranges are). Checking internal temperature is more accurate.

The view from the MSL front panel or Command View GUI is probably your best bet. It reads the internal temperature values from the drives and compares them against the internal temperature spec (for those drives - it's a slightly different spec for each drive type).

In your case, your drives are reporting 30C and 33C and that's well within the 15-67C range for internal temperature.

Another method which uses the internal temperatures is to pull a library and tape tools ticket and look at the drive temperature section. Should give the same values as the MSL GUI.

[Glen A. Harris]

The HP StorageWorks LTO-4 Ultrium 1760 Tape Drive Worldwide QuickSpecs shows:
"Temperature range Operating: 50° F to 95° F (10° C to 40° C) at a minimum of 6CFM airflow
If the drive temperature gets over 40° C, it is out of spec as per the QuickSpecs.
The Command View MSL status shows: "Internal Drive Temperature
(normal range: 15 °C - 67 °C)"
Which is the internal drive operational temperature limit? 40° C or 67 °C? Is there a definitive reference/spec?
Wouldn't tapes begin to stretch because of heat when the temperatue exceeds the limit?

[Richard Bickers]

Yes, 67C would be too hot if it was right in the tape path but the sensor is actually on the controller board and it's all a bit hotter there.

From our testing we know that an outside temperature of 40C translates to 67C (in this case) where the sensor is and that translates to the maximum temperature of the tape path (I don't have a figure for that). There's still a bit of margin before there's any impact on the write/read performance and more margin before there's any damage so the numbers can be a little approximate.

I agree it's confusing. We've talked about converting the figures from the sensor to something more meaningful but it depends on other factors (such as air flow) and we ended up leaving it as 'internal temperature'.

Our advice it not to worry too much about the actual number but do make sure it's within the limits as stated - i.e. <67C on the MSL view.

Do you have an issue you're trying to address? Your temperature appears to be OK but I'm thinking you wouldn't be looking at it if there wasn't an actual problem?