Date: Tue, 24 Jul 2012 16:30:58 -0400 From: Michael Powell <nightrecon@hotmail.com> To: freebsd-questions@freebsd.org Subject: Re: Disk Errors Message-ID: <jun0m2$f32$1@dough.gmane.org> References: <d65bfc394e4b31d92bb6ab9e8d220d16@dweimer.net> <20120724180421.GF38393@dan.emsphone.com> <e7e1dc818414243c7df4f1c7aca5e834@dweimer.net>
next in thread | previous in thread | raw e-mail | index | archive | help
dweimer wrote: [snip] > > SMART Attributes Data Structure revision number: 10 > Vendor Specific SMART Attributes with Thresholds: > ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE > 1 Raw_Read_Error_Rate POSR-- 117 099 006 - 145191418 [...] > 7 Seek_Error_Rate POSR-- 078 060 030 - 77590473 [...] > 195 Hardware_ECC_Recovered -O-RC- 025 023 000 - 145191418 [...] > 241 Total_LBAs_Written ------ 100 253 000 - 1480696469 > 242 Total_LBAs_Read ------ 100 253 000 - 922627427 [snip] Really, most of the numbers don't look really bad, but I'd cast a leery eye towards the way these three correlate. Read errors from bad spots in the magnetic media are one thing, but notice how the drive is recovering data with built-in ECC routines. Then notice that the seek error rate is moving along at a similar pace. There is a possibility that this is a purely mechanical weakness in the head positioning function, just barely "not bad" enough for to allow the drive to attempt to hide it through ECC. When I suspect media failure I generally use the manufacturers diagnostic utility to scan for defective media. I haven't used many Seagates in a long time so mostly this means WD's wddiags, which can be downloaded as a bootable CD .iso image. Seagate will have something similar. The quick scan is meant to be non-destructive while the long scan usually is. (I just had an old Raptor drive grow 5 bad spots recently, and the long scan fixed it without destroying any data - a first for me that) As long as the remap space area on the drive is not full usually these diagnostics have a good chance to fix bad spots. If it's an infrequent affair then one may just continue to use it. If I see new bad sectors a week later it is an indication that the drive has outlived it's usefulness and I replace it. If it's another year before I get a small handful of bad spots I may just let the diags fix it and continue to use. That is - as long as the remap space is not full. Once that happens any new bad spots are permanent and cannot be done anything about. Time to replace drive. The difference here is bad spots developing in the media on the platter(s) as opposed to the problem actually stemming from head seek position-location problems. None of the diags can do anything about head seek troubles, only identify if the problem is media on the platter(s) related. -Mike
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?jun0m2$f32$1>