• 2 replies
  • Latest Post - ‏2010-07-15T23:09:27Z by malahal
706 Posts

Pinned topic SAN disk on RHEL 5.4

‏2010-06-30T16:02:26Z |
I have installed rhel 5.4 with rdac driver and assigned the 8 LUNs from IBM DS 3400 storage. Server and storage is connedted with two Cisco MDS 9124 switch. Zoning is configured in both the switch. Server is having one HBA card with dual port and one port each connected to san switch. Storage controller is having two host port and each controller is connected to each san switch.

When i switched off the one san switch and fire the fdisk -l command in redhat it tackes time to come up with the output. This is a installation phase i want to know the working process in redhat. I have not checked with copying data to san disk from external source during powering off one switch.

Same type of configuration i have done in AIX i did not find any problem like this as mentioned above.
Will the data connectivity will loose for some second if one switch will fail?

If you have any suggestion are most welcome.
Updated on 2010-07-15T23:09:27Z at 2010-07-15T23:09:27Z by malahal
  • malahal
    4 Posts

    Re: SAN disk on RHEL 5.4

    Usually the DS3K works in active/passive mode where only one path is active. If
    you switch off one Fabric switch, the corresponding HBA should detect link
    down. After some timeout, the system should reject all I/O's on that path.

    If you use multipath, the multipath software will failover to working path
    after certain time period. All I/Os will be retried by the multipath driver
    after switching over to the working path. Applications will not notice any
    failure unless it is a tape drive related applications as some of the tape
    drive commands can't be retried.
  • malahal
    4 Posts

    Re: SAN disk on RHEL 5.4

    Does the slowness happen when you invoke 'fdisk -l" for the first time or every
    time? Please attach contents of /var/log/messages file when it is slow.