How would your determine a max value to set an alarm on the I/O activity of a ubuntu/linux server hosting upto 4 sites running apache, mysql and upto 4 tomcats?
Or in general (if there is one such) what is a suitable operational range for I/O read/write per second in a production server with a 7.2K SATA HDD?
What I’m trying to understand is the impact on the disks if read/writes per second peaks. What should I look for in the specification of the disks/drives to determine this?
As you can see, I’m “clearly” confused. Any help/direction would be appreciated…
The value at which the expected problems you’re alarming about are more expensive than the price of you having to pay attention to the alarm.
What number is that? That depends on a lot of things, including:
Which problems are you trying to avoid?
Do you worry about performance? If so, do you worry more about latency or throughput? How’s the tradeoff between interactive and batch-job performance?
Do you worry about wear-and-tear and the lifespan of the media? Do you worry about how often you have to restore backups?
Do you worry about the price of the disks? How much value is better disks going to bring to your operation?
How much can the writes be deferred? How much reading is preventable through caching? How lax can you be with respect to independence (the I in ACID)?
If you really want the best disk for your situation, these are some of the questions you probably want to ask yourself. If I were in your situation, I’d probably pick a random disk from the low to low-mid price range, and then see how it works out. Then you’ll have experience to learn from so you know what to do differently next time (if anything) and it’s not going to cost you much.