Cisco Headend Service Pack 2 for SR 2.2 3.2 Installation Guide
SR i4.5 Storage Requirements
41
Network Attached Storage (NAS)
NAS refers to storage that is shared between computers on a LAN or a WAN
interface. Where a SAN is specifically built for moving blocks of data between
computers and storage, NAS takes a general purpose network and adds storage
traffic into the mix. Access to NAS storage can be either ‘block level’ or ‘file level’,
based on what protocol is used over the network. iSCSI is an example of a ‘block
level’ protocol, and NFS is an example of a ‘file level’ protocol.
interface. Where a SAN is specifically built for moving blocks of data between
computers and storage, NAS takes a general purpose network and adds storage
traffic into the mix. Access to NAS storage can be either ‘block level’ or ‘file level’,
based on what protocol is used over the network. iSCSI is an example of a ‘block
level’ protocol, and NFS is an example of a ‘file level’ protocol.
Backup/restore in System Release 6.0 supports backups and restorations to and
from a network file system (NFS). A NAS device or an NFS server on the network
can provide the required NFS share. The rest of this appendix describes how these
choices are used and how to determine the amount of storage needed to
accommodate the backup needs. When discussing storage options there are three
factors that must be considered: cost, speed, and reliability. These factors are
discussed with each option.
from a network file system (NFS). A NAS device or an NFS server on the network
can provide the required NFS share. The rest of this appendix describes how these
choices are used and how to determine the amount of storage needed to
accommodate the backup needs. When discussing storage options there are three
factors that must be considered: cost, speed, and reliability. These factors are
discussed with each option.
For protection from all failure scenarios, a highly-available NAS backup is desired.
NAS can be placed in a separate facility from the iDNCS, and backup/restore
utilities can access the storage via a NFS mount-point provided by the NAS device.
What type of NAS storage is selected depends on how the factors interact at each
site. With NAS, all of the trade-offs on cost, speed, and reliability come into play.
NAS can be provided by anything from a small two-drive desktop enclosure, all the
way to a portion of a large EMC or NetApp storage array.
NAS can be placed in a separate facility from the iDNCS, and backup/restore
utilities can access the storage via a NFS mount-point provided by the NAS device.
What type of NAS storage is selected depends on how the factors interact at each
site. With NAS, all of the trade-offs on cost, speed, and reliability come into play.
NAS can be provided by anything from a small two-drive desktop enclosure, all the
way to a portion of a large EMC or NetApp storage array.
Disk vs.Tape Backup
The reasons for backing up data to disk instead of tape include:
Disk backups are faster; disk transfer rates are generally faster than tape,
resulting in shorter backup windows
Disk access is faster. There are no ‘seek delays’ for finding data and it is faster to
restore data
Disks, especially disks that are protected using RAID, are more reliable when
compared to tapes. There are no tapes to manage.
compared to tapes. There are no tapes to manage.