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SAN vs NAS for server backups?

Discussion in 'Tech Talk' started by betyourlife, May 12, 2010.


  1. betyourlife

    betyourlife
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    Let's say you have multiple servers spread out geographically. You want to store the backups of the servers off site so that if something happens to the site, the backups of the server aren't destroyed along with the server they were on.

    Would you use a SAN or a NAS to store the backups on? My vote would be for the NAS as it serves the need, is less complicated and more cost effective.

    Thoughts?
     

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    #1 betyourlife, May 12, 2010
    Last edited: May 12, 2010
  2. betyourlife

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    Bump....
     

    #2 betyourlife, May 13, 2010
    Last edited: May 13, 2010
  3. JimmyN

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    I use an NAS for remote web server backups, as well as backing up all the systems on my local network. SAN units are usually fibre channel based and are much more complicated to set up and configure as they are device based and work with disk blocks rather than being file based like an NAS. Unless you'd need a fleet of NAS units, and would prefer a single SAN, the NAS will likely fit your needs better.

    And you can cobble together your own NAS pretty cheap, all you need is an old outdated computer and some additional drives. I'm running FreeNAS as the OS, and built mine from an old Gateway P4 system that had been sitting around unused for a few years. You won't need a monitor or keyboard except during the initial installation of FreeNAS.

    FreeNAS is a pared down very minimal FreeBSD OS but includes SSH, rsync, FTP, SMB, BitTorrent, a web server, and other services ready to go. It includes just the things you'll need to run a NAS, plus a few little extra goodies. You can do a full install so it boots off a hard drive, or you can boot and run it from a thumb drive or CF adapter plugged into the IDE controller if you want to go diskless on the OS.

    Every night the NAS connects to the web servers using rsync and backs them up, then it backs up the mail and documents on my local network systems, as each Windows system also has rsync (DeltaCopy) installed, then the NAS backs itself up to an external USB drive. Every morning it sends me an email with status info, the results from the previous nights backups, SMART drive test results, etc.

    And in the meantime it also serves up DVD movies and music CD's to any system connected to the LAN as I have two drives on the NAS just for media files. As you can probably tell I love my FreeNAS box. Especially since the only cost was some additional drives, as the OS is free and the box was an old retired computer.
     
  4. stooxie

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    How and what are you backing up? You have some kind of backup software?

    As Jimmy said, SAN is more for local storage (difference being not direct attach) and doesn't do much in the way of geographical distances.

    That leaves NAS as the remaining choice but you still have plenty of architectural decisions to make based on requirements.

    -Stooxie
     
  5. meanmotorscooter

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    If you've got the money, then SAN. If you're on a budget, then NAS. A SAN has many more uses because of it's speed.
     
  6. Linux3

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    I have to go with a NAS. Network Attached Storage, as the name implies.
    SAN, Storage Attached Network is mostly used for local networks, I know not always, so multiple systems can share and increase storage. A SAN looks like local storage to the systems that link to it. Not really what you want.

    Now a NAS can be a SAN, it's a matter of attachment and networking but sorry I digress.

    If you are backing up multiple systems located all over then speed of the NAS and numbers of Ethernet ports is an issue. Think about how much data you want to back up and how long it takes to make that backup.

    A NAS is much easier to configure and maintain.
    Say you have 10 systems that are all getting backed up and it takes 4 hours across you LAN / VPN to back up each system. You should be looking at a NAS with more than one Ethernet port.
    I have 3 SUN Fire X4500 /X4540 systems. They each have 6 Ethernet ports. I run 4 way Bonding of each system into a 24 port Cisco switch. The other 2 ports per NAS are for local management. All my systems to be backed up are connected to one of the 3 NAS's via the Cisco switch. So, in effect I can have 12 simultaneous backups going. Easy.
    The Sun Fire X4500s are small but heavy boxes with 48 disks in each. Configure them in a RAID with a few hot spares and you have your NAS.
    No extra software required, unlike a SAN.
     
  7. trashcat

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    Depends on what type of backup you are doing.

    A SAN is designed to be primary storage for active data and is rather expensive, fast, reliable, and usually onsite support is included. Mostly think expensive, we are using mostly hp FC SANs and new disks are around $900 each for 300GB. We charge other departments about $5000 per TB which includes backup.
    Backup is on much cheaper SATA arrays that cost about $100 per TB and is NAS.

    If you're backing up to a hot site then use a full SAN because it may need to run all your business system when your primary site catches on fire or building maintenance does something stupid on the floor above your server room.

    If you're backing up just for recovery and data retention policies use NAS it's much cheaper and fast enough to restore one or two machine at a time. If you have remote sites then your data connection is going to be far slower than what a SAN can handle and you'd just be wasting money on features you can't use. Like only driving a sports car in a retirement community.
     
  8. betyourlife

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    Thanks for the responses so far. I would be backing up using windows server backup, with backup jobs scheduled afterhours during low use periods. The idea is simply to stop keeping backups at the local site, on the server that may very well be destroyed taking the backups along with it.

    It seems that we are in agreement on NAS being the better choice for the task. Simple, cheap and meets the need.
     
    #8 betyourlife, May 13, 2010
    Last edited: May 13, 2010
  9. area727

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    How are your different sites connected? What connection speeds are you looking at? That will most likely be the bottle neck. So would you really see the benefits of a SAN? I'd save the money and stick with NAS.
     
  10. betyourlife

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    I have plenty of bandwidth site to site so I'm not really concerned about bottlenecks. WAN outages don't concern me either since they are rare and short, plus I'm just using this as a storage solution not to run live applications.

    Yeah, the NAS was what I was leaning toward originally but figured I'd put it out to committee and see. Glad we are in agreement. Thanks for the input.
     
  11. njl

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    Neither.

    Thoughts? I don't think you know what NAS or SAN are.
     
  12. BigDog[RE]

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    I use a NAS that supports iSCSI to backup my exchange servers. relatively cheap, network attached, and because I use iSCSI, NTFS formatted, so I can do a granular backup of Exchange. A lot of the new NAS' support iSCSI now.
     
  13. Pierre!

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    NAS is good till it comes to patching the OS... and that used to be a tricky issue. You *BRICK* your NAS, you're in a world of FuN!

    iSCSI is very cost effective, can be expanded relatively easily, and does appear to be a local drive which is really cool for native SQL backups. In addition to this, you can purchase mirror software for your iSCSI SAN that might get you a mirror across a WAN, depending on available bandwidth, replication/mirror requirements, and data change rate.

    I had some very successful replication using Robocopy - throttling, scheduling, mirror, one way replication can be achieved pretty effectively.

    If you are just throwing it off site, check out Robocopy. Resist the temptation to use DFSR if the data is even moderately dynamic on Server 2003. I didn't get a chance to work with DFSR on Server 2008, but MS told me that it was for *static* data on Server 2003. Don't know that they would work too hard to change that going forward.

    Good luck, sounds like fun!
     
    #13 Pierre!, May 29, 2010
    Last edited: May 29, 2010
  14. Radian

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    they have different machines that may fit your budget. Basically you can host operating systems (or shares) over a block protocol (iSCSI or FC) or NAS (cifs of nfs). iSCSI is free on NetApp and pretty simple.

    Data replication is done with snapmirror, this replicates changes between your primary site to one or more secondary sites.

    This allows for multiple methods of recovery.

    The technology is very simple and the interface is refined and intuitive.
     
  15. Linux3

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    This is only an issue in the Windows world.
    Why, why would you run Windows on a NAS?
    Many vendors sell NAS solutions and have you noticed, they mostly do not run Windows.
    I can understand, well almost, why your servers run Windows but get a Unix based NAS, lock it down, don't make it visible to the world and just run it.
    I have Sun boxes from 2001 and they just run and run. Login as root only from the console. Only one network login and requires sudo to do anything.
     
  16. Pierre!

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    I believe these were early versions of NAS, and they sucked hard with the Win OS.

    Linux is clearly a heartier choice with NAS/SAN.
     
  17. vafish

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    Spread out geographically as in different cities?

    Unless you have fiber channel connectivity between the servers to the SAN there is no advantage to using the SAN.

    Your biggest limitation will be the bandwidth between your sites and the amount of data you need to back up.

    When you get everything on Fiber Channel connections then SAN makes sense.
     
    #17 vafish, May 30, 2010
    Last edited: May 30, 2010