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jskfanFlag for Cyprus

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The purpose of Windows Shadow Copy Limit

If I understand Windows Shadow Copy is used to hold Files and folders up to the size limit determined in Shadow Copy settings.
However there are some doubts about its usage such as:

** if Volume C: is 100 GB  and you set up Shadow copy site limit to 6 GB , how does the system determine which folders or files to keep in the shadow copy so, that if next day or week one of the files or folders get deleted, user can recover them from "Previous Version"

**There are also Backup products that use Shadow Copy, such as Veritas Netbackup that uses VSS. I wonder how Netbackup uses Shadow copy, even though I have read that it uses it for Snapshot.
 So if Shadow copy size limit is set to 6GB limit then if Netbackup needs more than 6GB would it delete the data  inside of it or it will just fail and abandon the backup job ?

So probably Microsoft Windows Expert and/or Backup Expert can answer this question

Any help will be very much appreciated.

Thank you
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David Johnson, CD
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Backup using Shadow copy's don't affect other shadow copies. And it is first in first out which means older files get removed until the newer files can fit.
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if there is not enough space on the reserved size of the Shadow Copy,as I mention 6GB is the Limit, where will backup write it is snapshot data ?

**if Volume C: is 100 GB  and you set up Shadow copy site limit to 6 GB , how does the system determine which folders or files to keep in the shadow copy so, that if next day or week one of the files or folders get deleted, user can recover them from "Previous Version"
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David ,

We are talking about 2 separate usages of Shadow copy
if you look at my initial question, it is about:

-- Windows shadow copy : which files and folders the system choose to save so that next day or week a user deletes a file, can be recovered using the "Previous Version" tab
--how Netbackup use Windows Shadow copy, if the limit size of 6Gb is reached will Veritas netbackup overwrite what is in the shadow copy or extends the size or put the data in different places

I know the :system volume information is the folder where shadow copy files are written to
net backup doesn't use the settings you set for shadow copies..  please re-read my previous comment #1 and #2
@jskfan - You should separate the two concepts. Shadow Copies are not backups and have different uses from backups.

Your question 1: Users can recover previous versions back as far as Shadow Copies go. That is the limit. It is not a date or time limit.


Your question 2: The backup you are referring to backs up the Shadow Copies. It does not change them so far as I know.
Also, Net Backup or any other backup does not increase the size (on a backup) of your Shadow Copies. You are still limited to 6 GB.
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OK Guys...

probably you did not understand my question:
let's start with Shadow copy that allows users to recover deleted files and folders

-- if you set the size limit of Shadow copy to 6GB, but the C: drive is 100GB
how is the system going to save 100GB inside Shadow copy which is just 6GB, so that the next day or next week if a file is deleted from C:drive, user will recover it from Shadow Copy using "Previous Version " tab.
To answer my question, is probably user will have to select which folder to be included in the Shadow copy?  I hope I am correct..
 

--- Well I do not have any answer or guess when it comes to Veritas Netbackup  VSS , (Shadow Copy)--
David mention system volume information, this is the physical folder that Windows Shadow Copy refers to.

So When Back up is initiated , the backup software writes Data into system volume information folder (Shadow Copy), then if the folder (system volume information) gets completely filled, and the backup software still needs to write data into Shadow copy , how is it going to work ?
how is the system going to save 100GB inside Shadow copy which is just 6GB, <-- It cannot. No way. So it saves only the newest files which is what we have said here.

user will recover it from Shadow Copy using "Previous Version " tab  <-- Yes BUT (BUT) only if it is there. If replaced by yet newer files, too bad. It will be gone.

the backup software writes Data into system volume information folder (Shadow Copy),  <-- I do not think so. No value in that. It would backup what is there.
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https://www.experts-exchange.com/questions/23581055/NBU-VSP-Cache-folder-is-getting-Big-and-Big.html

I looked up the above file...it explains the Cache folder that gets created by Netbackup
it is different than what Windows Shadow Copy for recovery of previous versions of files
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Thank you Guys
I will post Question about VSS later