When you backup a VM, you are getting a snapshot of the computer you are
saving,  if you later need to restore a specific file on that VM and you
didn't install the client then you only have the snapshot and you must
restore the entire snapshot, convert it back into a VM and then copy out
what you need.

We annually test our DR plan and last year was the first using VMs.  We
take a snapshot once every week and then use the client on each VM to get
the changes that are occurring daily.  During our DR test at IBM, we
restored the VMs, then brought it up to date using the windows client

If you don't use a client to get the indivdual changes at the file system
level, then you have to take a snapshot everyday and still deal with
restoring the entire VM and conversion when you need to do a restore.  We
are using 5.5 and have 3 ESX servers hosting 20 VMs.  We are in the
process of ordering another ESX server to increase our VM farm.

If we didn't also backup the individual file changes on each VM, we would
have to snapshot everyone each night and the amount of data being saved
each day would be about 25 terabytes despite the fact that only part of
the file system may have changed.  Also during our production season,
taking a snapshot on a active server will cause processes on that server
to be "delayed" while the snapshot log file is being created.  Everytime
this happens, our helpdesk gets calls from users saying that for several
minutes everything stopped.

TSM 6.x may change how this works, but we are using 5.5 with VCB and this
is how it works.  Been up and running more than a year now.


Buddy Howeth
Computer Operations Specialist
Information Systems
Pacific Coast Producers
Corporate Offices
631 N. Cluff Ave
Lodi, CA  95240-0756
(209) 367-8800 - Main#
(209) 367-6288 - Computer Room
(209) 366-6240 - Alpha Pager





Remco Post <r.post AT PLCS DOT NL>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
09/25/2009 07:00 AM
Please respond to
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


To
ADSM-L AT VM.MARIST DOT EDU
cc

Subject
Re: [ADSM-L] Backing up virtual machines






On 25 sep 2009, at 15:50, Buddy Howeth wrote:

> If you backup a V.M., you still need to install the windows client
> on each
> VM in order to get the file updates so there are no savings on
> licenses.

care to explain? The essence of VCB is to not have to install a client
on each VM.... And the number of clients installed actually has
nothing to do with the number of licenses you need, IIRC.

> We have about 20 VMs now which are backed up using VCB (Virtual
> Consolidated Backup).

--

Met vriendelijke groeten/Kind regards,

Remco Post

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