Senior LevelLinux Commands & SysAdmin
What is Device Mapper Multipathing (DM-Multipath) and how does it handle storage SAN path failover?
❓ Interview Prompt: Explain DM-Multipath, storage Area Networks (SAN), active-active vs active-passive path failover, multipathd daemon, and /etc/multipath.conf.
In enterprise Storage Area Networks (SAN), servers connect to Fibre Channel or iSCSI storage arrays via multiple physical Host Bus Adapter (HBA) paths:
DM-Multipath ('multipathd'):
Combines multiple physical I/O paths (e.g. '/dev/sdb', '/dev/sdc') into a single virtual multipath device ('/dev/mapper/mpatha'), providing automatic path failover and I/O load balancing!
Code Implementation Example
bash
# Display status of all active multipath SAN storage paths
sudo multipath -ll
# Sample output:
# mpatha (360050763008101680000000000000100) dm-0 IBM,2107900
# size=500G features='1 queue_if_no_path' hwhandler='0' wp=rw
# '-+- policy='round-robin 0' prio=1 status=active
# |- 1:0:0:0 sdb 8:16 active ready running
# '- 2:0:0:0 sdc 8:32 active ready running💡Inspecting enterprise SAN Multipath I/O path failover using multipath -ll.
🎯 Interview Key Takeaway
Use DM-Multipath to aggregate multiple SAN storage I/O paths into a single resilient virtual block device.
#DM-Multipath#SAN Storage#Multipathing#Senior
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