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My Hands-On Experience With POWER8

In June, my company received its first two POWER8 servers to use for testing. One server was a single-socket S814 with PowerVM, RHEL and AIX, and the second was a Linux-only box running PowerKVM and RHEL Linux. I had the privilege of working with the AIX server, which I attached to an HMC and our V7000 disk subsystem.

The Specs

The S814 is configured with the high-function backplane so it wasn’t a split backplane. It has 8 x 3.7ghz cores, 128GB of memory, 12 x 387GB SSDs, 4 x 300GB hard drives, 2 x dual port 16Gb Fibre cards, 2 x 4 port dual 10Gb and dual 1Gb FCoE cards as well as the 4 port 1Gb network card. I chose the FCoE cards rather than the new 10Gb network cards because they’re supported by network install manager (NIM). The S822L Linux only box has 10 x 3.4ghz cores and 64GB of memory with a 4 port 1Gbe adapter and 2 x 300GB hard drives. Because the S822L is running PowerKVM, it’s not connected to an HMC. This article will focus on the S814.

The S814’s high-function backplane means all disks and SSDs were on the same controller, which went to one VIO server. The second VIO server will be booted from SAN and configured later. I installed two client LPARs—one running AIX v7.1 tl03 sp3 and the other running AIX v6.1 tl09 sp3. The HMC was a CR7 and was installed at the latest MH01441, which is still the highest level.

The Setup

After connecting everything, powering up the server and flashing the microcode, I ensured the logical memory block or memory region size was set to the same as our other servers. This is required using live partition mobility and you must power cycle the box if you have to change it. The configuration and setup of the VIO and LPAR profiles was no different to any other server and very few differences were noted in the HMC GUI, so the setup was simple. Since the NIM server had been upgraded to AIX v7.1 tl03 sp3, the next step was to create the LPP source and SPOT for NIM for the new AIX v6 and v7 levels to be installed. Additionally, I used installios against the VIO server DVDs to create the necessary VIO resources on the NIM master.

The VIO images were also loaded to an FTP location on the NIM server. After creating the VIO profile, I booted the LPAR and checked the Yes box at the top of the activation pop-up that says, “Install Virtual I/O Server as part of activation process?” Once the VIO server was running, I went through all the normal checks. Ioslevel shows as and oslevel –s shows the operating system at 6100-09-03-1415. This means the VIO will be running in SMT4 mode since SMT8 requires 7.1 tl03 sp3. The following shows this is the case:

# smtctl
This system is SMT capable.
This system supports up to 4 SMT threads per processor.
SMT is currently enabled.

After setting up the VIO on two of the four internal disks, I then set up FBO (file backed optical) and loaded a bunch of ISO images for various sets of software. I always set up FBO if I have a spare disk as I tend to lose the DVDs. By ripping them to ISO images and uploading them to FBO, I can always find them and recreate the DVDs as needed. And, of course, I can load them remotely to any of the LPARs controlled by that VIO server. After setting up FBO, it looked as follows:

$ lssp
Pool              Size(mb)   Free(mb)  Alloc Size(mb)    BDs Type       
rootvg              540672     407552             512      2 LVPOOL     
fbovg              1089024     577024             512      1 LVPOOL     

$ lsrep
Size(mb) Free(mb) Parent Pool         Parent Size      Parent Free
  511414   490594 fbovg                   1089024           577024

From this, we can tell that the FBO pool is approximately 1TB in size with about half of that space unused.

$ lsvopt
VTD             Media                                                 Size(mb)
vtopt0          No Media                                                   n/a
vtopt1          No Media                                                   n/a
vtopt2          No Media                                                   n/a
vtopt3          No Media                                                   n/a

Finally, with the VIO server up and running it was time to create the client LPARs. I created an AIX v7 LPAR and an AIX v6 LPAR, both with an entitlement of three and six virtual processors (VPs) and 32GB of memory. Both were provided SAN-based disks via vSCSI from the VIO server. Once everything was running, I ran smtctl to check the LPARs. It turns out that by default the AIX v7 LPAR comes up in SMT4 initially. I ran ‘smtctl –t 8’ to change the AIX v7 LPAR to SMT8. vmstat shows an entitlement of 3 and logical CPUs (LCPUs) of 48 on the AIX v7 LPAR and LCPUs of 24 on the AIX v6 LPAR.

Jaqui Lynch is an independent consultant, focusing on enterprise architecture, performance and delivery on Power Systems with AIX and Linux.

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