Originally posted by: eventius

Hello,

We have some server of machine type-model : 8268-E1D

The embedded SAS controller reports as follows in ASMI:

FRU: Embedded SAS Controller (ES)
Part number: 00E3129
Serial number: YL10UF467004
FRU number: 00E2735
CCIN: 2B2D
RID: 0x4d00
Location code: U78AB.001.WZSKP6C-P1-T9

And from AIX we can see the controller as:

# lscfg | grep sissas
+ sissas0          U78AB.001.WZSKNYG-P1-T9             PCIe x4 Planar 3Gb SAS Adapter

But in running the various commands lsdev, lsdevinfo, lsattr etc. we do not seem to be able to report the cache size; in fact we are not sure if there is even a cache on this controller.  We also tried the diag command, but it would not let us run it on the controller, perhaps because the OS is up and in use.

Can anyone help us determine, either by part number or AIX commands, whether the controller has cache and if so how much?

Thanks!
 

Originally posted by: flodstrom

In case the "sissas0" is the only available SAS adapter then you likely don't have any cache for the internal controller.

Just to give you an idea, below is out put from an older machine (Power6) that has a cache for the internal SAS controller.

# lscfg | grep sissas
+ sissas2          U789C.001.DQD0B43-P1-C9-T1          PCI Express x1 Auxiliary Cache Adapter
+ sissas1          U789C.001.DQD0B43-P1-C4-T1          PCI-X266 Ext Dual-x4 3Gb SAS Adapter
+ sissas0          U789C.001.DQD0B43-P1-T9                 PCI-X266 Planar 3Gb SAS RAID Adapter

As for the size of the cache, don't know if it's possible to get or probe for that. I would advice to look at the man page for sissasraidmgr for more.

For example, a cached internal SAS adapter should look something like this.

# sissasraidmgr -L -l sissas0
------------------------------------------------------------------------
Name      Resource  State       Description              Size        
------------------------------------------------------------------------
sissas0   FFFFFFFF  Primary         PCI-X266 Planar 3Gb SAS RAID Adapter
 sissas2  00000000  AWC linked  Redundant cache protection for sissas0

Originally posted by: eventius

Thanks much flodstrom, that is most helpful. 

Originally posted by: j.gann

if still in doubt, you can use a tool like iozone and run it with direct-io (to bypass fs cache), constant block size and increasing file sizes.

adapter cache will show pretty obvious high write and/or re-read throughput as long as your file size is smaller than the cache.

there are some educating graphs in the iozone docs.

jg