ambient temperature on RS600s and SSA enclosures?? 1

[bi]

Does anyone know what the IBM recommended range for ambient temperature is for an SSA disk enclosure is? I can't seem to find it in my hardware doc or on their site. I'm trying to gather information for my upper management folks who think that a computer room with a consistent 78+ F (27+ C) temperature is OK. (and if someone can also tell me what the thermal sensors in an RS6000 is measuring, that would be great, too!)

I'm using the ssaencl and the uesensor command to gather info about the internal temp to show how it keeps rising through the day.

 

[aixqueen]

Not sure I agree...the colder the better to keep from frying...but
Maybe this will help?

Operating Environment
The following applies to Models D40 and T40:
Temperature: 10 to 40C
Relative Humidity: 8 to 80% (percent)
Maximum Wet Bulb: 27C
Operating Altitude: 0 to 2133 m (0 to 7000ft)
Input Electrical Power: 483 VA @ 208 V supply voltage
Capacity of Exhaust through max configuration: 41 litres/second
Maximum Noise Level: 6.6 Bels
Ground Leakage Current: 700 micro Amperes
Starting Current:
71 A for 100 microseconds,
9 A for one millisecond per power cord

http://www2.ibmlink.ibm.com/cgi-bin...nual^&type=D&search=7133-D40&title=T&product=

 

[bi]

Thanks, aixqueen.

I agree with you: I've been fighting this battle since last summer and now that the outside temp has started going up, the computer room is heating up again.

Is the temperature in the operating environment the temp in the computer room or the temp inside the enclosure?

 

[Yegolev]

Our datacenter is not only hot, it has carpet. Good luck fighting management, but don't get too upset about it. They are more concerned about the power bill they WILL receive rather than the degraded performance or shortened lifespan they MIGHT receive due to overheating.

Although in our case, we just don't have enough HVAC capacity. I believe that the IBM docs are ambiguous, so if I were you I'd interpret those temps in the manner that best suits your purpose. aixqueen is quoting the docs, so that's all you are going to get on temp range.

 

[bi]

At least we don't have carpet! We've already had to replace an SSA drawer, several disks, lost one LV (but I had a backup), and now we are thinking the heat may have something to do with performance of a database.

This may be a stupid question, but...

If the temperature of the computer room fluctuates widely during the day, will the performance of applications running on the system degrade and also fluctuate widely?

The application runs on an Oracle database. performance tests we have done sometimes have a test taking 2 to 3 times more than at other times. Would the higher temperature make the CPUs or disks or I/O cards "slow down"?

 

[bonsky]

Just wanna share regarding our experience in our data center recently. We are currently running an HA environment with 2 SSA drawer and running Oracle as well. I was on vacation when our aircon went down and no one bothers to look at the room though they were being paged by the system. By the time i went back to check the center after about 24hrs.. Whew! its burning hot there and you could actualy imagine how hot the temperature is.
But the thing is the machine failed over to the other one and all application still up and running though the room is definitely beyond the required temperature.
I supposed IBM machines have the strength and designed to widthstand such fluctuations of temperatures for "TIME". But then, you would hardly feel the degration of performance not until one of its component give up. If we are just talking about fluctuations of temperature here, i believed, you might have hard time proving it to your top management. you really need to work it out..

 

[avadh]

Hello,
The temprature has nothing to do with performance. Rs/6000 has built in temp sensor in the system that measure temp.
This is a typical thing i have seen with people running oracle on AIX.
If Oracel is sitting on jfs file system -> then do smitty aio -> change/show -> what the min, max and max request set to. increase min to 100, max 200, maxrequest to 12288.
do lslpp -l bos.adt.sample. check if this file set is installed or not.
if it is not installed install bos.adt.samples first then do command
/usr/samples/kernel/vmtune ->
if minfree is 120 maxfree is 128 and bottom of the output show maxperm=79.8%
then do this command.



/usr/samples/kernel/vmtune -p 15 -P 50 -f (120Xno of cpu) -R (f-F) -F (128*no of cpu)

right now do not have the right syntex to put this in /etc/inittab file.


2) go to

http://www.ibm.com

then search on hardware docs. you will find user manuals on system and also on SSA and it list what the temp in room should be.

 

[bi]

Hi avadh.

I thought something like tuning aio would help, but the DBA has set asynch in the database to be false. (he said something about it not available on a jfs -- it could only be used with raw volumes????)

I'm going to probably make the changes you suggest anyway. I have a question about your formula, though. should the -R parm be F-f instead of f-F? f-F would always give a negative number.

Thanks for your help.

 

[avadh]

Hello,

take the number you get for maxfree(F) then subtract minfree(f) and what ever is the result is maxpgahead(R).