Partitions configuration doubts

[Ninad_1]

Hi,

I am not very familiar with nPars and vPars though I have been reading some docs for a while. I have a few doubts which I need help on.
Say I have a rp7420 with 2 cells
Cell#1 8 CPUs (PA8900), 32 GB RAM
Cell#2 8 CPUs (PA8900), 32 GB RAM
The PCI-X IO cards as follows
PCI IO Chasis 0 -
Slot 1 - Core IO in slot
Slot 2 - 2 port Ultra 320,2 port GE card
Slot 3 - 2 port Ultra 320,2 port GE card
Slot 4 - 2 port FC (HBA), 2 port GE card
Slot 5 - 2 port FC (HBA), 2 port GE card
Slot 6 - 2 port Ultra 320,2 port GE card
Slot 7 - 2 port Ultra 320,2 port GE card
Slot 8 - 2 port FC (HBA), 2 port GE card
PCI IO Chasis 1 -
Slot 1 - 2 port FC (HBA), 2 port GE card
Slot 2 - 2 port Ultra 320,2 port GE card
Slot 3 - 2 port Ultra 320,2 port GE card
Slot 4 - 2 port FC (HBA), 2 port GE card
Slot 5 - 2 port FC (HBA), 2 port GE card
Slot 6 - 2 port Ultra 320,2 port GE card
Slot 7 - 2 port FC (HBA), 2 port GE card
Slot 8 - Free

Suppose I configure a single nPar with both the cells and above config. My question is can I have the following vPars configuration

vPar#1 - 8 CPU, 32 GB RAM, Using following cards
PCI chassis 0 - Cards in Slot 2,3,4,5

vPar#2 - 4 CPU, 16 GB RAM, using following cards
PCI Chasis 0 - Cards in Slot 6,7,8
PCI Chasis 1 - Card in Slot 1

vPar#3 - 2 CPU, 8 GB RAM, using following cards
PCI Chasis 1 - Cards in Slot 2,3,4,5

vPar#4 - 2 CPU, 8 GB RAM, using following cards
PCI Chasis 1 - Cards in Slot 6,7


My doubt is that vPar#1 is using CPU, memory and IOs from cell#0 and PCI chasis 0 and vPar#3 and 4 using resources from cell1 and PCI IO chasis 1. But vPar#2 is using CPU and memory from cell1 and using IO cards from PCI chasis 0 as well as chasis1 -
Is this a valid configuration,
Can I design such a system configuration ?

Please clarify my doubts and any tips/caveats.

Thanks a lot,
Ninad

[Duncan Edmonstone · Accepted solution]

Ninad,

vPars doesn't care what cell an IO card is part of, so this is a valid config, although I'm not sure whether you might need to make the core IO card part of one of the vPars.

As long as a vPar has CPU, memory and access to PCI card(s) with a storage port and network port then your fine.

HTH

Duncan

[Ninad_1]

Thanks for the help.
Is it possible for you to let me know whether I need to have the Core IO in any vPar ?
Also do I need the Ultra SCSI cards for boots disks or I can use SAN boot disks for nPar and all vPars in it ?
Also which storage model would you suggest for booting the 4 vPars mentioned above if I wish to boot through directly attached SCSI drives ? Can this storage array suffice the redundant connection as well for all the 4 vPars ?
Any guidance regarding this is most required.

Thanks again,
Ninad

[Mridul Shrivastava]

Core I/o is not required in vpar but it must have a SCSI card as each vpar requires a disk. Moreover vpar we need to assign LBA not SBA so if you have one scsi card for each vpar it will solve ur purpose.

[Ninad_1]

Yes I understand that I need to assign LBA (which will correspond to a card in a PCI slot) to a vPar.
Cant I use SAN boot for the vPars and nPar ?
Do I need to have a SCSI ?
I have seen quite a few threads discussing the SAN boot and SCSI boot options, but still not too sure on what should be the best practise ?
Also if I can use SAN boot, what will be the Core IO card required for, I am unable to understand.

Also I would like to know from the Gurus here - that if I have some vPars as production servers and some as development, then is it a good practise to have them as part of the same nPar, because the root user on development server will have privileges on the nPar and production vPars as well, so it seems a bit dangerous.
What are standard practices followed in your environments ?
But if I divide the development and production into seperate nPars, I wont be able to use the free PCI slots in production nPar and they will go waste.
Please suggest good practices and also please answer my above questions.

Thanks,
Ninad

[Torsten.]

Ninad,

as long as the HBA and the array is supported as a boot device, booting from SAN is no problem.
Consider to devide production and development systems for more stability. If you are root on a vpar, you are able to control the other vpars as well (reboot, start, stop...). You may use different npars for this, but this means a maximum of 8 CPUs per npar in your case.
I would configure the first vPar to boot from the internal disks, any other to boot from external devices (SAN).

[Ninad_1]

Torsten,

Thanks. Ya I understand that the root user will have administrative privileges on prodution vPars as well, but then we are loosing the PCI IO capability and hence will not be able to accomodate more vPars which would be possible CPU and memory wise but not possible due to inadequate PCI slots.
So I wish to understand how you guys have in your environments?

Thanks,
Ninad

[Ninad_1]

Also another thing I forgot - Torsten, you said I can use internal disks for one vPar, but then wont the Core IO card be a single point of failure for that vPar ?
How do you guys configure in your environments ?

Thanks,
Ninad

[Torsten.]

If you build a vpar with only one multifunction card, this card will always be a SPOF, even you have dual connectors on this card (e.g. 2 LAN interfaces - 1 card - 1 slot => the slot can fail).

Regarding the internal disks:
The upper HDDs are using a seperate SCSI controller each, the lower are sharing one bus.

Since you have all 4 internal disks in only 1 vpar, you can use 1 of the upper and 1 of the lower as a mirroring pair (SCSI controllers used for the left 2 HDDs are on the 2 MP cards, 1 one each card).

[Ninad_1]

Sorry for not being to able to understand fully.
Do you mean that you are suggesting to have 2 Core IO cards, then use 4 internal disks for the vPar and that vPar should use both the Core IO cards ? I thought I read that if a single nPar is configured only one Core IO card is active and the other comes into picture only if the 1st card fails. So can we use disks on the other Core IO card as mirrored boot disk ?
The other thing on having a single multi function card - If you see the configuration I have thought of - it consists 2 multifunction cards - so as to mitigate any single card failures - if that what you mean. Only the last vPar - vPar#4 has single instances of multi function cards - as there are not enough slots to plug in th cards, and now if you say I need 2 Core IO the only free slot will also be sacrificed.

Please do clarify my doubts.

Thanks a lot,
Ninad

[Torsten.]

It sounds complicated, but it isn't.

If you have 1 npar, you need 1 core I/O.

Please consider core I/O as a bundle of cards, the MP and the PCI card(s).

In fact, the internal disks are connected as follows:

1A - MP1
0A+0B - MP2
1B - Cell 1 slot 8

So disks 0A and 0B are on the same LBA level and must be in the same vPAR. You can add the other disks to this vPAR as well. Anyway, 1A, 1B and 0A+0B are pretty independent.

[Ninad_1]

Torsten,

Following is the text from the rp7420 instllation guide.
"Embedded Mass Storage
When hard disks are installed, the top two hard disk drives are controlled by cell 1 through its assigned
MP/SCSI Core I/O card. The bottom two hard disk drives are controlled by cell 0 through its assigned
MP/SCSI Core I/O card.
The DVD/CD/DAT removable media drive is controlled by cell 1 through its assigned MP/SCSI Core I/O card."

from which if I understand correctly the top 2 disks are on the same SCSI bus (as you have said already) and can be accessed thru the MP/SCSI card for cell1 whereas the bottom 2 disks can be used thru MP/SCSI card for cell0. Then when you say use one disk from top disks and one from bottom for one vPar - (Request you to answer the follownig questions in that sequence for my better understanding and flow of logic)
Q1) do you mean I use one Core I/O card or 2 cards ?
Q2) Can I connect one Core I/O card to one disk on top and other on bottom ?
If yes isnt this contradicting the text I pasted from the manual which say top disks - cell1 and bottom disks cell 0 ?
If no does this mean I need 2 Core I/O cards ? in that case doesnt it contradict that only one Core IO card is active at a time ?

Another question which is completely new - the CD/DVD drive is available only to cell1, in that case if I have 2 nPars do I need another DVD drives ?
What if I have 3 vPars in the 2nd nPar? Do I need to have a seperate DVD drive for each vPar ? Isnt there a simpler solution ?

Please help,
Ninad

[Torsten.]

Have a look at figure 2-2, perhaps this will answer your question

http://www.docs.hp.com/en/5991-1247/ch02s04.html#aes-npar-337

The "core I/O" in this case is the MP card, not only the PCI card. You must have 2 MPs installed to use all disks.

The upper 2 disks are using 2 different SCSI controllers and are connected to one cell together with the DVD drive.

The lower 2 disks are connected to the same SCSI bus and are connected to the other cell.

The picture will make this more clear.

[Ninad_1]

Torsten,

Do I have to say this seperately - isnt it evident - You are genius. and am very impressed as does all of your replies on this forum.
OR
I am pretty dumb. Lets not call me dumb so the above must be true :)

Now I understand what you meant by
1A - MP1
0A+0B - MP2
1B - Cell 1 slot 8

So just to confirm does this mean that the disk 1A is connected thru a seperate path directly to MP1 and disk 1B is connected thru slot8 to cell1.
Thus can I assume that the 2 disks 1A and 1B are on seperate physical paths and hence redundant. And I need only a single Core I/O card to connect these 2 disks for the vPar or rather nPar - Is that correct ?
Awaiting your reply before going home today :)

Also would it not be possible for you to clear my other question on CD/DVD ?
"Another question which is completely new - the CD/DVD drive is available only to cell1, in that case if I have 2 nPars do I need another DVD drives ?
What if I have 3 vPars in the 2nd nPar? Do I need to have a seperate DVD drive for each vPar ? Isnt there a simpler solution ?"


Thanks again,
Ninad

[Torsten.]

The second (PCI) core I/O is only needed if you have 2 npars. Notice, the term "core I/O" for this class of servers is not a single card, it consists of the MP and the PCI card.
If you have 2 cells and only 1 npar, you need the second MP and you *may* have a second PCI card, but you need only 1.

Each npar need a full pair of core I/O.

Hm, clearly enough?

Since the price for a SCSI controller is much lower since years before, you can find a lot of them inside a system. Usually there are dual bus controllers, 1 chip -> 2 busses.
e.g. the chip on Mp 0 serves the lower 2 internal disks (first bus) and the internal DVD (second bus).

Regarding the internal DVD:
Since it is below the LBA level you can use it from 1 vpar only. If you need *local* attached DVD drives, you need to attach one to every vPAR (you can connect an external drive to the partition if needed).
But in most cases you can work around. You can use an ignite server to install the OS and NFS for software installation.
In the rare case of need a local attached DVD, you can connect a standalone drive.

Another option is a FC connected (tape)drive. You can use several zoning configurations to make it available to the vPARS if needed.

e.g. you can use a library drive of a SAN attached lib to make ignite backups.