A few months I posted about my investigation of a performance problem on my 64-bit Windows laptop. Some mysterious source was doing transient 4 GB allocations which were evicting most data from the file cache. This was making my laptop rely heavily on retrieving data from its hard drive, and that is not a good thing.
My investigation with xperf showed that the problem was a bug in the driver for my recently purchased Western Digital My Book Live backup drive. The driver was telling Windows that the drive’s sector size was 4,294,967,295 bytes (4 GB minus one byte) and Windows was dutifully allocating that big a buffer.
Anyway, the cool thing about blogging is that it can be a great way to report bugs. After writing the original blog post I heard from Microsoft (they might put in a sanity check for the sector size, someday), and I heard from Western Digital. In both cases the contact was through unofficial channels, but I’ll take what I can get. Western Digital acknowledged the bug and promised to fix it.
I just heard back from Western Digital yesterday and apparently a fixed driver is now available. Version 126.96.36.199 was released over the weekend, so if you have this drive be sure to get the update.
It’s always great when the problems that I write about are actually fixed. While three months may not seem particularly agile it is actually really quick for most computer companies.
Unfortunately I can’t test the fix myself as I returned the drive already. If you have this drive and have seen this problem (requires a machine with more than 4 GB of RAM) then let me know if the fix works.
At least I did finally manage to conquer my backup difficulties, with a different external drive.
If you enjoy investigative reporting of performance issues you should take a look at the other articles in the series.