On Sun, Jan 04, 2004 at 12:36:42AM +0100, GCS wrote: > On Sat, Jan 03, 2004 at 04:52:06PM -0500, Andy Firman <[EMAIL PROTECTED]> 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. I have learned that LBA = logical block addressing and CHS = cylinder head sector. Not sure of the implications of using either. 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? > > Why would Western Digital > > make the drives different? Or did I do something wrong > > with partitioning/formatting? > No, partitioning is ok IMHO. What you don't know that hdd size is > calculated from a triplet: Cylinders, Headers, Sectors: > > Disk Drive: /dev/hda > > Size: 40000000000 bytes > > Heads: 255 Sectors per Track: 63 Cylinders: 4863 > > Disk Drive: /dev/hdd > > Size: 40020664320 bytes > > Heads: 16 Sectors per Track: 63 Cylinders: 77545 > If you do the math: C*H*S*512 => you should get the size in bytes. So > hdd has more Cylinders because it has less Heads value (this is not the > real value, but some kind of mapped one). > > > Do the physical drives and partitions have to be EXACTLY the > > same for RAID 1 to work properly or will the following > > layouts of my drives be sufficient? > Hmm. Note sure this is ok, try to set the same CHS for both drives. > > > /dev/hda1 * 1 122 979933+ 83 Linux > Also, if I remember right, a plus sign after the size is indicating a > warning that the partition does not on Cylinder boundary, which may be a > problem as partitions may overlap a bit. I noticed the plus signs but did not know what they indicated. 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. Thanks, Andy -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
