UE STorage Array Issues

[Richard Lundgren]

I have just come across a Compaq UE storage array box, which I am now tring to configure without too much success. When I create the array the only option I am able to select is 100% read / 0% write. On boot I do get an error saying to check the cables, but I have tried this array with 2 seperate cables and still have the same problem. I guess I either have a broken box or I am missing something somewhere. Any assistance would be very much appreciated. Thanks

[Marko H.]

You should enable the write cache on your controller in ACU - if you have such a controller.

Otherwise you have only this one option.

[Brian_Murdoch · Accepted solution]

Hi Richard,

The cache settings relate to the type of controller attached to the UE, not the UE itself. If your Smart Array controller has no battery backup for example then it won't be able to use write-back cache as there is no safeguard against power failure. If a controller fails or is powered off with unwritten data in the cache, it knows to write this data to disk when power is applied to the server again and it initialises. The batteries hold the data in the cache safely for up to 100 hours.

If there is no battery then it is forced to be a read only cache. This is not a fault it's just the type of Smart Array you have limits its configuration.

With respect to the cable error. I believe you will get this message if you only have drives attached to the external port on the array controller and none attached to the internal port. You will probably find that the errors state port 1 (Internal) as the source of the problem. What are the error codes generated (1775/1777 perhaps?).

I hope this helps.

Brian

[Richard Lundgren]

Thanks for the responses. I will check that error message to see exactly what it says. I guess I can now go ahead and install the OS which should provide hours of fun and enjoyment..... once again thanks.

Richard

[Richard Lundgren]

That error code is 1777, so looks as though I am ok. I am just getting something about RAID 4/5 running at reduced performance until disk consistancy check has been completed now. Any idea how long this might take? Thanks

[Brian_Murdoch]

Hi Richard,

The rebuild may be slow due to the fact that you have no write-back cache but it shouldn't be too long.

In larger storage configurations , for example the MSA1000 it's best to speed up the process by writing data to and from the logical drives or it can take a long long time to complete so if your drives can be seen by the operating system, start using them to speed things up.

Some 1777 errors are addressed by firmware updates. What model of raid controller are you using and what is it's current firmware revision (Both seen on the screen when the system boots).

Regards,

Brian

[Richard Lundgren]

Thanks Brian. OS installed and running with all configured. Well at least it was when I went to bed last night, only to wake up this morning with no power...nice to get a blackout in the middle of the night. Such is life. Could only manage to get redhat 8.0 installed as for some reason all of my other Linux distros didnt want to play, either couldnt find CD drive or various other issues, so RH 8 will provide a platform to upgrade from in any case. At least its working.

Yes the OS can see the logical drives, so will take your suggestion and start to use them.

Will have to get back to you on the controllers and versions. Cheers

Richard

[Richard Lundgren]

Brian...ok here goes with the controller information.

SMART-2SL
SMART-2/P
Smart Array 221

Those are the 3 RAID cards that I am currently running. Not sure of the version numbers as I got this info from the dmesg command in Linux.

What I have noticed though is that the OS (Fedora Core 2) only seems to be recognising 1 processor. Also disk writing is very very slow...something like 10 minutes to write 500 meg data across a 100 meg network connection. That doesnt sound right to me.

When I look at the arrays, on both of them both of the green lights are constantly on on each of the drives, and the centre light only goes off and / or blinks when data is being written to the disk, however in the main server array only the left side light is on, unless there is disk activity in which case the centre light will blink to signify this. ANy ideas or help with this one would be most appreciated also. Thanks

Richard