Ah, nothing to bring joy to the holidays like a bit of good old-fashioned sales craziness.
Recently we started seeing weird performance “guarantees” by some storage vendors, who seem will try anything for a sale.
Probably by people that haven’t read this.
It goes a bit like this:
Continue reading “Beware of storage performance guarantees”
<I understand this extremely long post is redundant for seasoned storage performance pros – however, these subjects come up so frequently, that I felt compelled to write something. Plus, even the seasoned pros don’t seem to get it sometimes… 🙂 >
IOPS: Possibly the most common measure of storage system performance.
IOPS means Input/Output (operations) Per Second. Seems straightforward. A measure of work vs time (not the same as MB/s, which is actually easier to understand – simply, MegaBytes per Second).
How many of you have seen storage vendors extolling the virtues of their storage by using large IOPS numbers to illustrate a performance advantage?
How many of you decide on storage purchases and base your decisions on those numbers?
However: how many times has a vendor actually specified what they mean when they utter “IOPS”? 🙂
For the impatient, I’ll say this: IOPS numbers by themselves are meaningless and should be treated as such. Without additional metrics such as RAID type, randomness, latency, read vs write % and I/O size (to name a few), an IOPS number is useless.
And now, let’s elaborate… (and, as a refresher regarding the perils of ignoring such things when it comes to sizing, you can always go back here).
Continue reading “An explanation of IOPS and latency”
This is going to be a short post, to atone for my past sins of overly long posts but mostly because I want to eat dinner.
On storage systems with spinning disks, a favorite method for getting more performance is short-stroking the disk.
It’s a weird term but firmly based on science. Some storage vendors even made a big deal about being able to place data on certain parts of the disk, geometrically speaking.
Continue reading “What is hard disk short stroking?”