Intel Responds To X25-M Fragmentation Issue

Vigile writes "In mid-February, news broke about a potential issue with Intel's X25-M mainstream solid state drives involving fragmentation and performance slow-downs. At that time, after having the news picked up by everyone from CNet to the Wall Street Journal, Intel stated that it had not seen any of these issues but was working with the source to replicate the problem and find a fix if at all possible. Today Intel has essentially admitted to the problem by releasing a new firmware for the X25-M line that not only fixes the flaws found in the drive initially, but also increases write performance across the board."

Comments

Anandtech

[MSG]

On this subject: I finally got around to reading Anandtech's very long article about the current crop of SSD drives. I feel like it was pretty educational, which is good because it took a long time to digest.

In its discussion of performance degradation as drives are used, the article explains that individual pages of NAND memory can't be rewritten. Early in a drive's life, page are remapped when they are rewritten by the OS. As the drive is used, the drive runs out of pages to remap and is forced to copy a block (typically a 512KiB collection of 4KiB pages) to cache, erase the block and then rewrite the block with the new pages. That explains pretty well why write performance degrades, since writing to a block that has data must perform a read and erase operation in addition to the write. However, that explanation also leaves open the question of how the drive prevents data loss if it loses power. Worst case, the OS issues a write and the drive copies a 512KiB block to cache and erases the block, and then loses power. Due to remapping, literally anything could be in that half a MiB. The data loss could corrupt the file that was being modified, obviously, but also any other file on the drive, or parts of the filesystem itself.

I figure there's got to be protection against data loss built-in, but I'm not able to find details regarding any individual drive or manufacturer's approach to solving that problem. Does anyone know more about this subject?

You should be looking at random I/O speeds

[Chris Daniel]

The new OCZ & Samsung drives are faster (and larger) than the X25-M.

For sequential read/write -- yes, they are faster than Intel's offerings. Random read and write operations, on the other hand, are another story. That's one of the biggest issues that SSDs solve versus spinning platters, and no one has gotten it right so far, except Intel.

Re:You should be looking at random I/O speeds

[LordKronos]

I think you misunderstood. Your experience vs. mechanical drives has nothing to do with the issue. The AC said that the OCZ was faster than the Intel. Chris Daniel was simply saying "yes the OCZ is a bit faster for sequential acces, but random access (which is what most users experience the most) is better on the Intel"

If you look at Anand's article You will see that the OCZ beats the Intel slightly at sequential read (about 5%), and by a decent margin on sequential write (slightly less than 3x). However, these aren't things most users typically do...especially the writes. You are only likely to be doing that if you are working with editing large a/v files or something, and since large a/v files take up tons of space, a SSD probably isn't the best candidate for that anyway, given its current cost/storage metric. The OCZ might make sense working in a something like a professional AV editing environment, where you can copy the file off the server, work on it locally, and then copy it back to the server when done.

On the other hand, random reads and writes are something that virtually 100% of users experience on a regular basis, and this is where Intel really shines. On reads, Intel wins by a decent margin (slightly less than 2x the speed, and nearly half the latency). But then look at sequential writes, and Intel really takes the decisive win in that category. While the OCZ is a healthy 4x faster than Velociraptor, the Intel is just shy of 10x the performance of the OCZ (and thus nearly 40x the Velociraptor).

So, when you compare the Intel and the OCZ, the Intel loses slightly and decently on 2 operations that are less common, and it wins decently and decisively on 2 operations that are more common. Thus it's a pretty good stretch to try and say the OCZ is faster than the Intel.

Customer Experience

[robvangelder]

I once dined at a restaurant that took my order, but minutes later realised they couldnt make it due to stock shortage. I got a different meal, and they told me mine was for free!

The way a company recovers from a problem can actually turn into a net positive experience for the customer.

In my case, I'm turned from an unsatisfied customer, to an advocate. For sure, I've recommended friends dine there since then.

Every interaction is an opportunity to delight the customer. Even those events that at first feel like a disaster unrolling.