Sunday, September 21, 2008

sports tracker on the nokia e71

Lots of people seem to experience freezes of Nokia Sports Tracker on their E71 smartphone. Google easily finds articles suggesting a workaround: "don't leave Nokia Sports Tracker in the foreground". However, that doesn't help. What does help, is setting the access point to "None" in the Nokia Sports Tracker settings. The program doesn't like an inaccessible access point in its preferences.

Friday, September 5, 2008

a plea for non-identical mirrors

When I set up my test environment earlier this year, I put two Samsung HD103UJ 1TB drives in the main file server, and configured them as a RAID-1 software mirror through mdadm. Just months later, smartd was spewing out messages about both drives: Device: /dev/sda, 8 Currently unreadable (pending) sectors.

That got me very worried... I replaced one of the drives with a WDC WD1000FYPS-01ZKB0, and rebuilt the mirror. Actually, I built new mdadm mirrors from smaller partitions to lessen the risk of a two-drive badblock scenario. Regardless, my data got moved, so now everything gets stored on two different drives. Different makes, manufacturers, models. Same size though.

The problem is, I can't RMA the drive. It's still in warranty, but when running badblocks -w on the drive, it shows no problems whatsoever. Moreover, the SMART status has gone back to: Current_Pending_Sector 0. So not only is the problem undetectable by badblocks, it even makes it go away in the SMART counters where it was visible in the first place.
First I thought that the problematic sectors got reallocated, but the SMART info suggests otherwise: Reallocated_Event_Count equals 0. If you want to look at your own drives, grep for _Pending_ and Reallocated_ in the smartctl -a output.

My conclusion: it was a very, very bad idea to make a mirror out of two identical drives (and aggravating the fact, they were the cheapest ones, too). Please remember: pick different drives to make up a mirror. A mirror image needs to be identical, but having it on identical media is a bad, bad thing.

And to round up, my final thoughts: how bad is a non-zero "Current_Pending_Sector" count, really ? And why can it go down without reallocation ?

Side note: I'm not saying Samsung drives are bad, I have 3 Samsung HD300LJ in a RAID-1 setup that are doing fine after more than 2 years of 24x7 service. But buying their 1TB drives left a sour aftertaste...