What is SAN Storage ???
A storage area network (SAN) is a secure high-speed data transfer network that provides access to consolidated block-level storage.
A SAN makes a network of storage devices accessible to multiple servers. SAN devices appear to servers as attached drives, eliminating traditional network bottlenecks. SANs are sometimes also referred to as SAN storage, SAN network, network SAN, etc. While a single server can provide a shared hard drive to multiple machines, large networks may require more storage than a single server can offer. For example, a large business may have several terabytes of data that needs to be accessible by multiple machines on a local area network (LAN). In this situation, a SAN could be setup instead of adding additional servers. Since only hard drives need to be added instead of complete computer systems, SANs are an efficient way to increase network storage.
SAN Server Side Configuration on CentOS
1) Install the iscsi pkgs & start services
# yum install *scsi*
# service tgtd start
2) creates a target with id 1
# tgtadm –lld iscsi –op new –mode target –tid 1 –T iqn.2011-
09.com.galaxy:storage.disk1.linux.sys1.xyz
3) To view the current configuration
# tgtadm –lld iscsi –op show –mode target
4) Add a logical unit to Target
# tgtadm –lld iscsi –op new –mode logicalunit –tid 1–lun 1 -b /dev/sdb1
5) To view the details
# tgtadm –lld iscsi –op show –mode target
6) To enable the target to accept any initiators
# tgtadm –lld iscsi –op bind –mode target –tid 1 -I ALL
SAN Client Side Configuration
1) To discover targets at a given IP address
# iscsiadm –mode discovery –type sendtargets–portal
2) To check at client run fdisk and mount
# fdisk -l
# mkdir /mnt/clientsan
# mount /dev/sdb1 /mnt/clientsan
