On Sat, Aug 20, 2011 at 08:43:09PM +0200, Alex Samorukov wrote: > > >"The SMART tests you did didn't really amount to anything; no surprise. > >short and long tests usually do not test the surface of the disk. There > >are some drives which do it on a long test, but as I said before, > >everything varies from drive to drive." > > > It is not correct statement, sorry. Long test trying to read all the > data from surface (and doing some other things). > > // one of the smartmontools developers and sysutils/smartmontools > maintainer.
That's great, but too bad it's generally not true in practise. Dan's long scan on his site proves it, and I've dealt with this situation myself many times over. SMART long tests *may* do a surface scan, but in most cases they just seem to do something that's similar to "short" but over a longer period of time. Furthermore, some which *do* do a surface scan on a "long" test don't always report LBA failures in the self-test log. I've personally seen this happen on Western Digital disks (model strings are unknown, I'm certain I've rid myself of those drives). Firmware bug/quirk? Possibly, but at the end of the day it doesn't matter -- it means the end-user has wasted 2-3 hours for something that tests OK yet we know for a fact isn't OK. I *have* seen a drive do a surface scan on a "long" test and report LBAs it couldn't read, but as I said, it's rare and varies from vendor to vendor, drive to drive, and firmware to firmware. When it happened I was very, very surprised (and delighted). The only thing I can trust 100% of the time when it comes to surface scans is SMART selective scans (if available, which again the OP's drive does not offer this), or using dd or a read-per-LBA on the OS level (which works everywhere). -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB | _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
