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HP Disk Modules

Posted: Sun Apr 30, 2017 2:19 pm
by pentium
I have an A3515A Intelligent disk array and I've noticed it uses the same style sleds as my D350. They seem to come in both LVD and HVD flavours, marked with a yellow or purple SD or DF sticker on the front of the module and either SE or DF stamped on the PCB inside (but the components on both types of PCB are identical in values and placement).
I do not have enough of either type module to completely populate the array so I am wondering if I could just remove all the SE disks and fill them all with HVD drives or if there's something else I've missed that makes them incompatible with eachother.

Yes I am aware you should never mix HVD and LVD disks. I'm just wondering if the modules are the same in that regard.

Re: HP Disk Modules

Posted: Thu Jan 25, 2018 2:39 pm
by psergiu
The difference between HVD, SE & LVD is the signaling voltage. LVD is 1.2V, SE is 5V, HVD is up to 12V. With HVD you can have a disk 25m away from the server. I did managed a HP server with 24m SCSI cables.

The rule is - if you have any "smarts" in the box, you have to use what it says on that "smart" piece of equipment. For a 12H Autoraid, you can only use what the controller boards support.

If you have just a plain JBOD box (like A3312A "Jamaica") - you can put in any compatible disks, as long as you don't mix different ones on the same bus.

Re: HP Disk Modules

Posted: Thu Jan 25, 2018 5:36 pm
by pentium
I don't know what by definition of "smarts" each drive carrier has.

Re: HP Disk Modules

Posted: Fri Jan 26, 2018 10:55 am
by kjaer
The first thing I'd check is whether the grounds are all tied together. This would rule it out for use with any differential signalling.