1. Set up the storage to allow access to the LD(s) by the server following the NEC storage user guides.

Transcription

1 Overview Server running Red Hat Enterprise Linux (RHEL) must be configured to recognize and work with NEC storage systems. The following procedure demonstrates the steps necessary to configure multipath software native to RHEL to attach to newly created LD(s). System Requirements This procedure has been tested on both the D and M series storage arrays. Procedure 1. Set up the storage to allow access to the LD(s) by the server following the NEC storage user guides. 2. Verify that server sees the two paths to the LD(s). I created one 166GB LD, added it to LD set for my server and got the following response after rebooting my server. [root@localhost etc]# ls /dev/sd* /dev/sda /dev/sda3 /dev/sda6 /dev/sdi2 /dev/sdi5 /dev/sdt /dev/sda1 /dev/sda4 /dev/sdi /dev/sdi3 /dev/sdi6 /dev/sda2 /dev/sda5 /dev/sdi1 /dev/sdi4 /dev/sds The paths to my LD are /dev/sdt & /def/sds 3. Edit /etc/multipath.conf file to include the NEC disk array. a. cd /etc/ b. cp multipath.conf multipath.conf.org c. vi multipath.conf

2 d. Include the following lines: defaults { udev_dir /dev polling_interval 10 selector "round-robin 0" path_grouping_policy multibus getuid_callout "/sbin/scsi_id -g -u -s /block/%n" prio_callout none path_checker readsector0 rr_min_io 1000 rr_weight priorities failback manual user_friendly_names yes blacklist { devnode "^(ram raw loop fd md dm- sr scd st)[0-9]*" devnode "^(hd xvd)[a-z]*" vendor "*" product "*" blacklist_exceptions { #for M-Series vendor "NEC" product "DISK ARRAY" #for D-Series vendor "NEC" product " istorage" devices { vendor "NEC" product ".*" features "1 queue_if_no_path" no_path_retry queue e. Exit and save the changes. 4. Verify the multipathd deamon run levels a. chkconfig list grep i multipath b. if it s not on for levels 2345 do the following steps i. if multipathd was not in the list do the following: chkconfig --add multipathd ii. chkconfig multipathd on iii. multipath On my system I got the following output indicating that I have two paths to one LD [size=155g][features=1 queue_if_no_path][hwhandler=0][n/a] \_ round-robin 0 [prio=2][undef] \_ 3:0:0:0 sds 65:32 [undef][ready] \_ 4:0:0:0 sdt 65:48 [undef][ready]

3 iv. /etc/init.d/multipathd start

4 5. Verify that the pointer has been constructed for the LD a. ls /dev/mapper On my system I now get the following output [root@localhost etc]# ls /dev/mapper/ control mpath2 6. Created a system partition [root@localhost etc]# fdisk /dev/mapper/mpath2. The number of cylinders for this disk is set to Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder ( , default 1): 1 Last cylinder or +size or +sizem or +sizek ( , default 20233): Using default value Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 22: Invalid argument. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks. 7. Reboot the system 8. After rebooting the system verify that a pointer now exist for the partition created in step 6. [root@localhost ~]# ls /dev/mapper/ control mpath2 mpath2p1 9. Create a file system on the newly created partition on the LD. [root@localhost sbin]# mkfs.ext3 /dev/mapper/mpath2p1 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Superblock backups stored on blocks:... This filesystem will be automatically checked every 23 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

5 10. Create a mount point. mkdir /nec_ld 11. Edit fstab to include the newly created LD /dev/md2 / ext3 defaults 1 1 /dev/md4 /home ext3 defaults 1 2 /dev/md1 /var/crash ext3 defaults 1 2 /dev/md0 /boot ext3 defaults 1 2 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode= sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 /dev/md3 swap swap defaults 0 0 /dev/scd0 /media/cdrecorder auto pamconsole,exec,noauto,managed 0 0 /dev/mapper/mpath2p1 /nec_ld ext3 defaults 0 0

6 12. Check the mount point. sbin]# mount -a sbin]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/md % / /dev/md % /home /dev/md % /var/crash /dev/md % /boot tmpfs % /dev/shm /dev/mapper/mpath2p % /nec_ld