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Storage space requirments for back up RRS feed

  • Question

  • Quick question. If I have 2GB of storage space allocated for my files. Do I need 2GB of space for back-up? Unlike a RAID?

     

    Thanks

    Monday, February 26, 2007 6:22 PM

Answers

  • It depends. I don't know about the compression of the backups, but I do know that WHS utilizes single-instance-storage, meaning that if you are backing 4 identical machines (e.g. Windows XP with Office 2003), all of those files would be stored only once on the server, and all of the backups would have "shortcuts" to the actual files, drastically reducing the total size needed for backups. As to how much a given file takes up space wise, that really depends on the situation.

    That part speaks to the client backup.  As for the server backups, at this time, there's not specifically a server backup per se at the moment.  Instead, there's a "folder duplication" checkbox that you can enable for each of your folders.  Once you enable this feature, a full copy of each file is copied to an additional drive on your machine (kind of like RAID 1).  This isn't real-time, but done over time silently using, I believe, the new Drive Extender tool in WHS.

    Hope that helps...
    Monday, February 26, 2007 6:56 PM
  • Backups appear not to be compressed at all. I monitored disk space utilization as I backed up each of the machines at home for the first time. In particular, I looked at the folder that actually contains the backup images.

    I found that, for each machine, that first backup matched (in terms of server storage utilization) the disk usage on the machine being backed up, within a very small (<1%) margin of error.

    I can confirm that for you tonight, if you would like. Disk usage on the home PCs won't have changed significantly in the past week, and the initial backups are still there.
    Monday, February 26, 2007 8:14 PM
    Moderator
  • Backups are not compressed, however, they do use something like single instance storage.
    Tuesday, February 27, 2007 11:00 PM
    Moderator

All replies

  • It depends. I don't know about the compression of the backups, but I do know that WHS utilizes single-instance-storage, meaning that if you are backing 4 identical machines (e.g. Windows XP with Office 2003), all of those files would be stored only once on the server, and all of the backups would have "shortcuts" to the actual files, drastically reducing the total size needed for backups. As to how much a given file takes up space wise, that really depends on the situation.

    That part speaks to the client backup.  As for the server backups, at this time, there's not specifically a server backup per se at the moment.  Instead, there's a "folder duplication" checkbox that you can enable for each of your folders.  Once you enable this feature, a full copy of each file is copied to an additional drive on your machine (kind of like RAID 1).  This isn't real-time, but done over time silently using, I believe, the new Drive Extender tool in WHS.

    Hope that helps...
    Monday, February 26, 2007 6:56 PM
  • Backups appear not to be compressed at all. I monitored disk space utilization as I backed up each of the machines at home for the first time. In particular, I looked at the folder that actually contains the backup images.

    I found that, for each machine, that first backup matched (in terms of server storage utilization) the disk usage on the machine being backed up, within a very small (<1%) margin of error.

    I can confirm that for you tonight, if you would like. Disk usage on the home PCs won't have changed significantly in the past week, and the initial backups are still there.
    Monday, February 26, 2007 8:14 PM
    Moderator
  • Backups are not compressed, however, they do use something like single instance storage.
    Tuesday, February 27, 2007 11:00 PM
    Moderator
  • If backups are not compressed, how can the first backup I perform take 48GB of used space (with only 2.5GB excluded) and back it up into only 23GB of space on the WHS? (this is before any other PC has been backed up)

    If that's not compression there's some magic going on :-)

    Since that first backup I've had 4 nights of backups for the 3 PCs connected and in total they are using 35GB of space. They do appear to be compressed, and they make great use of single instance storage.

    Wednesday, February 28, 2007 12:02 AM
  • I too am amazed or puzzled by the storage space reported in the connect console. I have 129GB of files on my client machine that has been backed up on WHS that shows as only 48GB. Even when you add the 5GB of shared folders, this is still over a 50% decrease in size.

    With Beta 2, I had a storage use of over 110GB. Did something change in CTP? How can we be sure that the files are all there?
    Wednesday, April 25, 2007 3:46 PM
  • There's a post elsewhere in the forums from (I think) Dileep from Microsoft where he basically says "Yes, the pie chart is fairly broken." Apparently the CTP has a bug in the space reporting. But it's entirely possible for a PC to back up into less space than it looks like it occupies, and still not be compressed beyond what Single Instance Storage does, between space allocated on disk due to cluster sizes (a 1k file in a 64k cluster occupies lots of space that won't get backed up, for example), large chunks of file that are actually empty (databases are famous for compressing ridiculously because of exactly this...), etc. I would guess that the differences you're seeing are due to one or more of these factors.
    Wednesday, April 25, 2007 5:07 PM
    Moderator