Unable to access swap disk

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 6.0
  • Multipath

Issue

  • Attempting swapon /dev/sda1 results in Device not found, despite fdisk and parted both showing the device and partition.

Resolution

  • Commented out the blacklist section, restarted multicast, and adjusted the reference to the device using the multipath name instead of /dev/sda.

Root Cause

  • The swap device was on a multipath consisting of one path, and the multipath wwid was being blacklisted.

Diagnostic Steps

  • Examined multipath -ll and saw:
mpathd (3600508b1001030393941334242301000) dm-0 HP,LOGICAL VOLUME  
 size=279G features='1 queue\_if\_no_path' hwhandler='0' wp=rw  
 `-+- policy='round-robin 0' prio=1 status=active  
 `- 2:0:0:1 sda 8:0  active ready running
  • Examined /etc/multipath.conf and saw:
blacklist {  
  wwid 3600508b1001030393941334242301000/  
}

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