On Sun, Jan 04, 2004 at 01:56:48PM -0500, Andy Firman wrote: > On Sun, Jan 04, 2004 at 12:36:42AM +0100, GCS wrote: > > On Sat, Jan 03, 2004 at 04:52:06PM -0500, Andy Firman <andy@firman.us> wrote: > > > Second, I have 2 Western Digital drives. > > > Both model WD400BB but they were manufactured about > > > 6 months apart. > > It may be an other revision, hdd controllers can have different > > chipset/'bios'. Also, they may have higher density plates, so less of > > them enough for the same capacity. > > > > > I partioned both disk's exactly the same using cfdisk > > > during the install. It seems that one drive has 4863 cylinders > > > and the other has 77545 cylinders. > > Can be a BIOS setting, check that both drives use the same addressing > > method (CHS, LBA, other). > > Both drives were set as "auto" in the BIOS. ...in which case it's almost certainly using LBA for both drives. > I have learned that LBA = logical block addressing and > CHS = cylinder head sector. Not sure of the implications of using either. CHS refers to sectors on the drive by a triplet of numbers specifying which cylinder, head and sector you want to access. It runs into all sorts of annoying limits due to different bits of software not having enough bits to store usefully large values for one or more of the numbers, and flawed algorithms for translating between the various fudges which are used to overcome these limits. LBA just numbers the sectors sequentially, so you have one great big number and that's it; much less chance for confusion. > Should I try using either and do my partitioning all over again > or should just accept the fact that 2 exact same model WD drives > does NOT mean they are the same physically? As has been said the 6-month difference in purchase date probably means that what is nominally exactly the same model is in fact trivially different. This sort of thing sometimes causes problems buying spares for cars, but it won't screw your RAID up. You'll just get a RAID volume of a size appropriate to the smaller of the two drives. If you're feeling fussy you could repartition the slightly larger drive with 2 partitions so as to use the extra 20664320 bytes for something else, but I reckon it'd be more trouble than it's worth. (cue nostalgia about when 20MB was enormously huge :-) ) > Maybe the best thing to do is get started with the root on RAID project > and see if these 2 "same model but different" drives cause any grief. Yes, and chances are it won't. -- Pigeon Be kind to pigeons Get my GPG key here: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x21C61F7F
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