Kind of a long hiatus posting (far too busy working on cool stuff) and for you looking for a deep technical post this may not be it… but here goes anyway since the content may also apply to my more usual subjects.
Recently I decided to discard my Luddite membership card and join the hordes of people using network-based services for music.
Continue reading “Is convenience devaluing products? Does quality suffer because of it?”
It was with interest that I watched some of EMC’s announcements during EMC World. Partly due to competitor awareness, and partly due to being an irrepressible nerd, hoping for something really cool.
BTW: Thanks to Mark Kulacz for assisting with the proof points. Mark, as much as it pains me to admit so, is quite possibly an even bigger nerd than I am.
So… EMC did deliver something. A demo of the possible successor to VNX (VNX2?), unavailable as of this writing (indeed, a lot of fuss was made about it being lab only etc).
Continue reading “How to decipher EMC’s new VNX pre-announcement and look behind the marketing.”
As the self-proclaimed storage vigilante, I will keep bringing these idiocies up as I come across them.
So, the latest “thing” now is selling systems using “Raw IOPS” numbers.
Simply put, some vendors are selling based on the aggregate IOPS the system will do based on per-disk statistics and nothing else.
They are not providing realistic performance estimates for the proposed workload, with the appropriate RAID type and I/O sizes and hot vs cold data and what the storage controller overhead will be to do everything. That’s probably too much work.
Continue reading “So now it is OK to sell systems using “Raw IOPS”???”
<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”
<Article updated with more accurate calculation>
There are some impressive new scores at storageperformance.org, with the usual crazy configurations of thousands of drives etc.
When looking at $/IOP, make sure you are comparing list price (look at the full disclosure report, that has all the details for each config).
Otherwise, you could get the wrong $/IOP since some vendors have list prices, others show heavy discounting.
Continue reading “Interpreting $/IOPS and IOPS/RAID correctly for various RAID types”