General Backup and
Restore
With SSL certificate checking in vSphere 5.1
and after, DNS services must be configured in the backup proxy, otherwise
SSL_Verify will fail with the “no host found” error.
For incremental backup of virtual disk, always enable changed block
tracking (CBT) before the first snapshot. When doing full restores of virtual disk,
deactivate CBT for the duration of the restore. File-based restores affect change
tracking, but disabling CBT is optional for partial restore (file level restore), except
with SAN transport. CBT must be deactivated for SAN writes because of thin-provisioning
and clear-lazy-zero operations.
Backup software should ignore independent disks
(those not capable of snapshots). These virtual disks are unsuitable for
backup. They throw an error if a snapshot is attempted on them.
When using VMware Tools debug
logging with quiesced snapshots, do not log
vmtoolsd.data
to a local file on the VM, such as
C:\Temp\vmtoolsd.log
.
Instead set
vmtoolsd.handler=vmx
to use the tools service.
To back up thick disk, the proxy's datastore must
have at least as much free space as the maximum configured disk size for the
backed-up virtual machine. Thick disk takes up all its allocated size in the
datastore. To save space, you can choose thin-provisioned disk, which consumes
only the space actually containing data.
If you do a full backup of lazy-zeroed thick disk with CBT deactivated,
the software reads all sectors, converting data in empty (lazy-zero) sectors to actual
zeros. Upon restore, this full backup data will produce eager-zeroed thick disk. This is
one reason why VMware recommends enabling CBT before the first snapshot.
With CBT enabled for backups on an NFS datastore,
thin-provisioned virtual disk may be turned thick upon restore, unless the NFS
server supports
lseek(...SEEK_DATA)
,
ioctl(...FS_IOC_FIEMAP)
, or
equivalent function.
Do not make verbatim copies of configuration
files, which can change. For example, entries in the
.vmx
file point to the
snapshot, not the base disk. The
.vmx
file contains
virtual-machine specific information about current disks, and attempting to
restore this information could fail. Instead use
PropertyCollector
and keep a
record of the
ConfigInfo
structure.