m. allan noah wrote:
> the eide electrical interface does not support hot-swap. i have done
> hot-remove many times, but not hot-add. seems like a nice way to lose a
> drive.
I tested the following:
Redhat 5.2 kernel 2.0.36 + raid 0145 + raidtools 0.90
RAID5 setup consisting of 3 partitions: /dev/hda1 /dev/hda2 /dev/hdc1
( yes the first 2 partitions are physically on the same drive, but at the
testing time
I had only 2 drives -:) )
I wrote a script that copies many files to the RAID5 array,
at some point I disconnected the data cable of the hdc drive (but not the
power cable) (secondary master),
then the kernel gives many errors like eide: IntrCmd
and then the usual I/O errors on /dev/hdc1 .
the RAID code spit out many debugging messages,
plus a strange
"md: raid bug found in line 666 ( calls the procedure MD_BUG )
what does means this ?
the kernel disabled the drive: in /proc/mdstat is can see: /dev/hdc1[0] (F)
raidhotremove /dev/md0 /dev/hdc1 works without problems
I reconnected the hdc drive ,
ran
fdsik /dev/hdc
and the kernel says me: ide1: reset
I removed the hdc1 partition and recreated it with id 0xFD , and then leaved
fdisk.
raidhotadd /dev/md0 /dev/hdc1
the kernel began to reconstruct the parity on the disk,
and all seemed ok.
but I am very courious if a one can really damage an EIDE drive doing
hot-adds ?
As you know the price/performace of the latest EIDE drives are very good,
especially if you look at the IBM Deskstar 16GB or the upcoming IBM 24GB
drives,
using 4 drives you can build a huge Raid array for a very competitive price,
and the performance is not so bad ( the IBM 16GB drives does a nice 12MB/sec
read transfer).
Yes SCSI is superiour to IDE, but software RAID adds much realiability to
these drives.
the maximum would be having even (realiable) hot-swap on IDE drives,
but I if you say it is not possible in a realiable manner .....
:-(
Do you know precisely what can be the factor which can damage the IDE drives
?
thank you for the infos,
best regards,
Benno.
