Hello to all,
I have a few questions about the status of
the Software RAID on Linux.
I am interested in the hot-swap , hot-add/remove
features of the current alpha Sotfware RAID for Linux.
1) I downloaded the alpha version of the 0.90 raidtools
and there are programs like raidhotadd and raidhotremove,
but the included RAID5.HOWTO file does not cover these commands.
The Howto says "if you connect a new drive" the kernel will
reconstruct the lost data on this drive"
but I think you must first partition the drive with fdisk
with the same size as the other drives in the array.
But is there a way to tell the kernel: "ok the new drive is ready,
reconstruct all the data" ?
Does anyone of you know if there are a way to
hot-add EIDE harddrives like the SCSI harddrives using
the echo >/proc/scsi/...
if this is possible, does someone know how to perform this task.
can this be emulated through the SCSI emulation on IDE device ?
Or does the EIDE hardware architecture not permit this ?
To support hot-reconstruction do you must set
#define SUPPORT_RECONSTRUCTION 1 in linux/md.h ?
(I think yes)
2) The RAID5.HOWTO says that you can autostart an md device at boot-time
without having to mdadd all the devices.
(this is archieved through changing the partition ID to 0xFD)
Does allow this feature to boot of a RAID5 array giving to LILO
/dev/md0 as root device , or is this autostart feature only available
for non-root md devices ?
3)
I tested the stock 2.1.132 linux kernel
the docs say it can boot off from a software RAID array throug passing
to LILO the parameters on the boot commandline.
But only RAID0/linear is supported.
Do you know if 2.2.0 support booting off from a RAID5 array
or if the only solution is making an initrd which mdadds all the devices
and then starts the array ?
thank you for all the infos.
best regards,
Benno.
