readme.multipath

iscsi-init LINUX boot

    Starting from 4.0.2.1 iscsi-init is multipath ready. So far it has been tested for FC3 and
RHEL4. If you test it for other distro's, please let me know. To make it work please follow the
steps below:

1. Download and compile multipath-tools from http://http://christophe.varoqui.free.fr
   Use latest vesrion from http://christophe.varoqui.free.fr/multipath-tools/
   Please keep in mind devmap_name, multipath and kpartx must be compiled statically.

2. Device-mapper should be from at least 2.6.10-rc*-udm2. For RHEL4 and FC3 I've just
   compiled and replaced DM modules. You will actually need dm-mod.ko, dm-multipath.ko,
   and dm-round-robin.ko

3. Compile statically scsi_id. You can find the source code in hotplug package.

4. Get wwid using scsi_id like this "/sbin/scsi_id -g -u -s /block/sda"
   It will need for multipath.conf to provide name consistency for root devnode.

5. Sync /etc/fstab with alias for wwid in multipath.conf.

6. Configure your target for multiple portal groups. For NetApp filers you'll have to
   enable iswt on at least two interfaces.

    A modified initrd for FC3 could be like below:
--
bin
  *devmap_name
  *insmod
  @hotplug -> /sbin/nash
  *kpartx
  @modprobe -> /sbin/nash
  *multipath
  *nash
  *scsi_id
  *udev
  @udevstart -> udev
dev
  -console
  -null
  +ram
  -sstty
  -tty1
  -tty2
  -tty3
  -tty4
etc
  udev
     rules.d
        multipath.rules
     udev.conf
  iscsi.conf
lib
  crc32c.ko
  dm-mod.ko
  dm-multipath.ko
  dm-round-robin.ko
  ext3.ko
  iscsi_init.ko
  iscsi_sfnet.ko
  jbd.ko
  libcrc32c.ko
  md5.ko
  scsi_mod.ko
  scsi_transport_iscsi.ko
  sd_mod.ko
  tg3.ko
loopfs
proc
~sbin -> bin
sys
sysroot
var
  run
  tmp
tmp
*init
--

IP.cfg for PXE could be like below:
--
TIMEOUT 50
PROMPT 1
DEFAULT  linux_iscsi_root
LABEL linux_iscsi_root
    KERNEL vmlinuz-2.6.10-1.770_FC3smp-iscsi
    APPEND root=/dev/system1 initrd=initrd-2.6.10-1.770_FC3smp-iscsi.img iscsi-if=eth0:192.168.1.10:255.255.255.0:192.168.1.1,eth1:192.168.2.10:255.255.255.0 iscsi-initiator=iqn.1987-05.com.cisco:01.26ffb046ec iscsi-target=192.168.1.2,192.168.2.2:iqn.1992-08.com.netapp:sn.16804546
    LABEL disk
    LOCALBOOT 0
--
Please keep in mind that you can achieve the same results using DHCP. In this case your IP.cfg
could be as simple as:
--
TIMEOUT 50
PROMPT 1
DEFAULT  linux_iscsi_root
LABEL linux_iscsi_root
    KERNEL vmlinuz-2.6.10-1.770_FC3smp-iscsi
    APPEND root=/dev/system1 initrd=initrd-2.6.10-1.770_FC3smp-iscsi.img iscsi-if=eth0,eth1
    LABEL disk
    LOCALBOOT 0
--

---------------------------------------------------
Igor Feoktistov <[e-mail]>