EVA4000 throughput

[Vincent Fleming · Accepted solution]

A couple of things...

First off, if you use 15k drives, you can get 200 IOPS per disk, BUT, that's pushing it in a database (ie: random small-block I/O) environment. You're more likely to see more like 100 IOPS per disk in random environments.

It all depends on how random you I/O is - the more you make the heads seek, the fewer I/Os it will be able to do. (it takes time to seek the heads)

So, distrubute the load over as many drives as you can afford.

Second, use at least 2 LUNs. That way, you will use both controllers. Here's my suggestion - create one LUN for the dataspaces, and one LUN for the logs. Both should be in their own disk group (ie: 2 disk groups). The logs should be at least 3 drives, maybe 4. The rest can go to the dataspaces.

Use Vraid-1 - much faster.

Watch which path is your primary path to avoid doing all your I/O through the wrong controller, as Uwe mentioned above.

Good luck,

Vince

[Uwe Zessin]

Load balancing...
well, what operating system are we talking about?

Remember that you need a multipath filter between the EVA and the file system handler.

According to your profile, you seem to deal a lot with HP-UX. Last time I checked, PVlinks cannot do any multipath load balancing. The traditional way is to create multiple virtual disks, access them via different primary paths and do the balancing (implicitly) via striping.

Another way would be Secure Path V3.0F - the AutoPath component supprts some kind of "dynamic load balancing".

[Vincent Fleming]

Yeah, but you want to be careful with the load balancing. You don't want to balance across controllers, because of the I/O forwarding behavior.

It's good to balance over multiple ports on the same controller, though.