Configuration
Three Red Hat Linux Virtual Machines clustered.
The three Linux Virtual Machines systems in the cluster shared a single ESXi host.
A database application each night dumped the database data to a directory on a separate disk.
Data Protector 8.x did a simple file level backup of the dump directory.
Problem
Every night, for random different files, there were errors
[Minor] From: VBDA@alpha.company.org "alpha.company.org [/srv/diskbackup]" Time: 11/26/2015 8:04:25 AM
[81:78] /srv/diskbackup/dbs/Ambridge/cm/cmcal.d13
Cannot read 107176 bytes at offset 1530920960: ([5] Input/output error).
[Minor] From: VBDA@alpha.company.org "alpha.company.org [/srv/diskbackup]" Time: 11/26/2015 8:04:25 AM
[81:78] /srv/diskbackup/dbs/Ambridge/cm/cmcal.d17
Cannot read 104008 bytes at offset 2097152: ([5] Input/output error).
[Minor] From: VBDA@alpha.company.org "alpha.company.org [/srv/diskbackup]" Time: 11/26/2015 8:04:31 AM
[81:78] /srv/diskbackup/dbs/Ambridge/cm/cmservicesc.d1
Cannot read 9144 bytes at offset 357171200: ([5] Input/output error).
Solution
After changing the configuration so each of the three Linux Virtual Machine systems, in the cluster, had their own individual ESXi host, the backup worked each night without error.