Re: performance of internal vs san for 7TB

According to IBM you MUST use a dedicated pool for production IBM i and
they recommend on using at least the same amount of vDisks than internal ,
desirable 80 GB LUNs , and at least the same amount of physical disks.
Cache has big inpact on performance. Use always 15 k disks.

I could mention: On EMC VMAX use Raid10 2+2 or Raid1 for production
systems, and Direct Attach is better than SAN attach. Use 8Gb FC HBAs.
Use DB2 SMP and try adding as much memory as possible. Always dual VIOS.
0.5 cpu and 4gb is enough for VIOS in most cases.
For DRP system maybe you are ok with Raid5, but try to avoid mixing servers
in the same disk pool.

El mié., jun. 3, 2015 4:35 PM, Sue Baker <smbaker@xxxxxxxxxx> escribió:

Steve Pavlichek
<spavlichek@xxxxxxxxxxx> wrote on
Tue, 02 Jun 2015 15:13:58 GMT:

Best way to confirm acceptable performance would be to use
Disk Magic. Short cut would be to request to have the same
number of disk drives (Physical drives, not LUNs), same speed
(15k or 10k) and that they be dedicated drives, not shared
with other hosts. It is also important when they configure
the LUNs to present to the LPARs, that the LUNs are similar in
size and quantity to your physical disk configuration.

Disk Magic only supports IBM storage. No mention of the vendor
for SAN storage has been made.

Depending on %full, more physical disk devices may be required
in the SAN due to drives per parity set and hot spare
requirements.

Sharing the arrays in the SAN may or may not have an impact on
results. If not sharing reduces the number of drives backing
the LUN significantly, this may result in poorer performance.

Similar size isn't a requirement. Similar quantity is advised,
which is likely to translate to similar size.


--
Sue
IBM North America Advanced Technical Sales Support (ATS) Power
Systems
Rochester, MN

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