UNIX for Dummies Questions & Answers

hi all,

anyone knows how to test ssd using iozon, I am currently running iozone and I don't know if it is testing the ssd or just the RAM...

anyone knows a good tutorial (like a step-by-step)?
cannot find any in google..

Thanks!

The trouble with attempting to test disks is that you can never really be certain that you're reading data that hasn't been cached somewhere.

A good way to try and dump what's in cache is to be testing a disk that's larger than the available memory. Once you've written out more data than you have memory you should be able to read back (sequentially) and be sure that it's not from memory. What size mem/ssd are we talking?

I tend to use bonnie++ to test disks BTW. Try and clear the memory from each write before reading, I would have posted a link to how that's done but I don't have enough points...

Hmmm, but I can still test using iozone? well that's the required tool so I don't have any choice...the size is 128GB and I just need to know if the results I get is correct...

what I do is mount the ssd then type this command

Code:

iozone -a -f /mnt/ssd/tempfile

then I get an output of columns and I know it's the KB/s rate for writing, reading, etc. and I don't know if the output is good or not...

I need to interpret the output to check if the ssd is Ok or not..

Providing iozone reads and writes more data than you have RAM available then your tests should be correct.

The problem occurs when you read or write that which could potentially exist in disk buffer. Writing out more data than you have available RAM will certainly reduce this chance.