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RAID 5 and Multi Terabyte Volume (Greater the 2TB) RRS feed

  • Question

  • All,

    Seems this question has been asked before and I am still struggling with it... and figured someone maybe able to offer some guidance

    I am trying to finish a WHS install and like the availability and "fail protection" of RAID 5... and all that I have read made be believe WHS does not play well with RAID 5 as you can quickly exceed the 2 TB limit of MBR.

    so... is it possible to get GPT setup on say a array with 4 1.5TB drive in RAID 5?  Service pack 1 should have had it in there... as a carry over from Server 2003

    The reason for my asking is I have been doing some poking around and have found a few commercial solutions that are talking about RAID 5, WHS and 7 TB of storage on a single volume.  VidaBox RackServer

    the Only way to accommodate this is to have a single volume or having the raid controller carve into 2TB chunks (this is what I did)  but this would create additional overhead and I believe reduce performance.

    I am currently using a 3ware 9500s-8 and it should give me screaming performance

    " The 3ware 9500S hardware RAID controllers deliver in excess of 400 Mbytes per second (MB/sec) sustained RAID 5 reads and over 100 MB/sec RAID 5 sequential writes with less than 3% CPU utilization"

    But my configuration is so slow... I have not measured it yet, but using TeraCopy it was only 5-20 MB/s

    So questions are:
    1. Is it possible to setup a volume greater than 2TB using GPT (or something else)
    2. Thoughts on how to improve write speed
    Thanks

    Chris
    Tuesday, April 7, 2009 8:49 PM

Answers

  • As you probably know, RAID with Windows Home Server is unsupported. It will usually work, but it's up to you to figure out configuration of the RAID hardware, and if you have a problem with your server, the RAID hardware may well make recovery more difficult.

    As regards your question, you can create an array of any size you like, but Windows Home Server will format any "drive" it's given using the MBR style of partition table, so it will use a maximum of 2 TB on a single volume. A viable workaround is to define multiple logical volumes of 2 TB on your array, as you suggest. VidaBox doesn't say, but I suspect that's what they do. Or they may be modifying Windows Home Server in some (unsupported) fashion to get it to use a GPT disk, then use online array/volume expansion to "grow" the storage when a disk is added. I don't know, and they don't say on their web site. :)

    For an individual such as yourself, if your RAID HBA supports online array expansion your best bet would be to simply configure additional volumes of 2 TB or less as needed and give them to Windows Home Server. Since you're using RAID for online data protection against the loss of a disk, you don't need share duplicaiton turned on. YOu should still plan to back your server up regularly, however. Protection against a single failed disk does no good if you experience simple OS corruption, or if you have a fire at home that destroys your server and all the data on it.

    I'm not on the WHS team, I just post a lot. :)
    Tuesday, April 7, 2009 10:36 PM
    Moderator
  • A GPT partition table won't have any effect on performance. And it's unsupported. The performance you describe is not unreasonable for gigabit ethernet; it's likely that's where any bottlenecks lie.

    As for VidaBox, they don't give any specifics on what they're doing. I very much doubt that "a lot of people" are using similar hardware, though; good quality RAID HBAs are pretty expensive. My guess would be that they use a combination of a RAID HBA that supports online array expansion, plus simply creating additional volumes on the array as disks are added and putting those "disks" in the storage pool. How exactly that's handled isn't at all obvious; from the screen shots it doesn't look like there's any interface that would let an end user trigger the process.

    I'm not on the WHS team, I just post a lot. :)
    Wednesday, April 8, 2009 4:58 AM
    Moderator
  • What I can see on their site makes me believe that whoever told you that is either misinformed or not truthful. With multiple "disks" in the storage pool, and duplication turned on for some of the shares per their own screen shots, their server is making use of the Windows Home Server disk management function.

    As for the "RAID is supported" claim, by VidaBox, perhaps. By Microsoft, not at all, and OEMs are prohibited from putting RAID arays in their home server devices. VidaBox probably doesn't qualify as an OEM; I believe there's a volume requirement for that. That would make them a system builder, and system builders have greater latitude than OEMs.

    Finding a RAID HBA that supports extending an array while it's on line isn't too tough. All you have to do is spend some money. And a fairly substantial fraction of those also support the online expansion of individual volumes on the array.

    There's a Windows Home Server "SDK" that you might want to take a look at...
    I'm not on the WHS team, I just post a lot. :)
    Friday, April 10, 2009 6:16 AM
    Moderator

All replies

  • As you probably know, RAID with Windows Home Server is unsupported. It will usually work, but it's up to you to figure out configuration of the RAID hardware, and if you have a problem with your server, the RAID hardware may well make recovery more difficult.

    As regards your question, you can create an array of any size you like, but Windows Home Server will format any "drive" it's given using the MBR style of partition table, so it will use a maximum of 2 TB on a single volume. A viable workaround is to define multiple logical volumes of 2 TB on your array, as you suggest. VidaBox doesn't say, but I suspect that's what they do. Or they may be modifying Windows Home Server in some (unsupported) fashion to get it to use a GPT disk, then use online array/volume expansion to "grow" the storage when a disk is added. I don't know, and they don't say on their web site. :)

    For an individual such as yourself, if your RAID HBA supports online array expansion your best bet would be to simply configure additional volumes of 2 TB or less as needed and give them to Windows Home Server. Since you're using RAID for online data protection against the loss of a disk, you don't need share duplicaiton turned on. YOu should still plan to back your server up regularly, however. Protection against a single failed disk does no good if you experience simple OS corruption, or if you have a fire at home that destroys your server and all the data on it.

    I'm not on the WHS team, I just post a lot. :)
    Tuesday, April 7, 2009 10:36 PM
    Moderator
  • Ken,

    Thanks... I have read some of the post on how to get GPT to work and I cannot figure out if I would get greater performance.  Right now it is painfully slow.  I will have to play around with the configurations I guess.

    Based upon other post it seems the system would be faster if there is only one disk.

    Is it possible to remove the data volume on the system disk?  This may help speed things up also.

    VidaBox makes it sound like they can add disks to add capacity as needed.  Since a lot of people are using the devices similar to what they are doing it would be great to figure out what they are doing. 

    Thanks

    chris
    Wednesday, April 8, 2009 2:09 AM
  • Ken,

    Thanks... I have read some of the post on how to get GPT to work and I cannot figure out if I would get greater performance.  Right now it is painfully slow.  I will have to play around with the configurations I guess.

    Based upon other post it seems the system would be faster if there is only one disk.

    Is it possible to remove the data volume on the system disk?

    No.  But that partition isn't used until last anyways.

    This may help speed things up also.

    VidaBox makes it sound like they can add disks to add capacity as needed.  Since a lot of people are using the devices similar to what they are doing it would be great to figure out what they are doing. 

    Thanks

    chris

    Wednesday, April 8, 2009 2:37 AM
    Moderator
  • A GPT partition table won't have any effect on performance. And it's unsupported. The performance you describe is not unreasonable for gigabit ethernet; it's likely that's where any bottlenecks lie.

    As for VidaBox, they don't give any specifics on what they're doing. I very much doubt that "a lot of people" are using similar hardware, though; good quality RAID HBAs are pretty expensive. My guess would be that they use a combination of a RAID HBA that supports online array expansion, plus simply creating additional volumes on the array as disks are added and putting those "disks" in the storage pool. How exactly that's handled isn't at all obvious; from the screen shots it doesn't look like there's any interface that would let an end user trigger the process.

    I'm not on the WHS team, I just post a lot. :)
    Wednesday, April 8, 2009 4:58 AM
    Moderator
  • A GPT partition table won't have any effect on performance. And it's unsupported. The performance you describe is not unreasonable for gigabit ethernet; it's likely that's where any bottlenecks lie.
    Actually I have slow disk to disk transfer as I was doing a "re installation" as my system disk died and transferring from one array (out side of the pool) to another (in the pool).  Something maybe wrong with my configuration as it still seems slow... and if there should not be any delta in performance between one volume and multiple volumes...I must have something set wrong.   CPU usage on the transfers (internal) are 3-5%

    As for VidaBox, they don't give any specifics on what they're doing. I very much doubt that "a lot of people" are using similar hardware, though; good quality RAID HBAs are pretty expensive. My guess would be that they use a combination of a RAID HBA that supports online array expansion, plus simply creating additional volumes on the array as disks are added and putting those "disks" in the storage pool. How exactly that's handled isn't at all obvious; from the screen shots it doesn't look like there's any interface that would let an end user trigger the process.

    I'm not on the WHS team, I just post a lot. :)

    Yea I did not mean same hardware but similar functionality goals of storage or large amounts of video (DVD, BD) and streaming them to end devices. (I maybe wrong)  As the storage requirements get bigger and users are looking to streaming to more devices, having a good hardware RAID will increase the amount of data you can stream (with a higher price). 

    thanks for the comments ken... I will do some more research and see what I can find 8-)

    Chris
    Wednesday, April 8, 2009 1:25 PM
  • so I have not given up on this quest yet.

    I asked the folks at VidaBox and Hot some interesting information and thought I would share here

    ;Our RackServer is based on WHS, but we don't use its disk management function directly. We've come up with a unique/proprietary setup such that RAID is supported nicely and works very well. Full online expansion is supported, and there is no 2TB limit because of MBR limitations either.



    so don't know exactly what their doing but I have to believe it is GPT if they are not using the native disk management functions

    is there a developer guide for WHS that I would be able to dig into?  Maybe this would give some ideas

    Thanks

    Chris
    Friday, April 10, 2009 1:24 AM
  • What I can see on their site makes me believe that whoever told you that is either misinformed or not truthful. With multiple "disks" in the storage pool, and duplication turned on for some of the shares per their own screen shots, their server is making use of the Windows Home Server disk management function.

    As for the "RAID is supported" claim, by VidaBox, perhaps. By Microsoft, not at all, and OEMs are prohibited from putting RAID arays in their home server devices. VidaBox probably doesn't qualify as an OEM; I believe there's a volume requirement for that. That would make them a system builder, and system builders have greater latitude than OEMs.

    Finding a RAID HBA that supports extending an array while it's on line isn't too tough. All you have to do is spend some money. And a fairly substantial fraction of those also support the online expansion of individual volumes on the array.

    There's a Windows Home Server "SDK" that you might want to take a look at...
    I'm not on the WHS team, I just post a lot. :)
    Friday, April 10, 2009 6:16 AM
    Moderator
  • I have read most if not all of the Vidabox info as well as traded posts and emails with Vidabox. Here is what I gather.

    The OS is installed on 1 volume that is MBR. The RAID array ( hardware based so I am told) is a totally separate volume that is GPT and is NOT presented to Drive Extender. Now I have seen the pictures of the Rackserver and RackerServer+ (raid expansion chassis) and the chassis appears to be using port multipliers. So I doubt it is truly a hardware based raid system. Although it does APPEAR to be a nice setup. I have actually figured out a way to do it with TRUE HARDWARE RAID but it is pricey (much cheaper than Vidabox).
    • Edited by b_weeks Wednesday, August 12, 2009 10:51 PM change
    Wednesday, August 12, 2009 10:50 PM
  • They would have to be using an SIL3124 based raid card with 2 internal/2 external ports that supports OCE (online capacity expansion) and port multipliers on all ports.
    Wednesday, August 12, 2009 11:03 PM
  • yea... but it has to be part of the main array since they are using mymovies  The program requires that the movies be on the share (so that I have seen) but I could be wrong
    Wednesday, August 12, 2009 11:13 PM
  • They aren't using any default share made by WHS, they manually create a "My Movies" share on the RAID array. The MyMovies is not configured to point to the System drive on the server.
    Wednesday, August 12, 2009 11:32 PM
  • This is from the Vidabox documentation for MyMovies. • Shared Folder Permissions & how they work First, note that these steps are already done on your VidaBox. You may want to walk through these steps as a refresher, and to confirm these settings. To share a folder on the server machine so that extenders can access them, right click the folder you would like to share, and click Properties. Under the ‘Sharing Tab,” click on “Advanced sharing”, confirm that the “Share this folder” checkbox is checked. Secondly, permissions must be granted to each extender. Since the user accounts have already been created, you can allow permissions to “everyone” with “Full Control” to allow read & write access to the folder. Don’t worry, “Everyone” is not really “Everyone”, but only “Everyone” created as a user on the host machine.

    When linking to your shared movies from within My Movies, or when configuring folder monitoring to monitor a file system, it is important to point My Movies to the shared part of the file system. All VidaBox servers have their default movie storage set to \\[Server name]-[Serial Number]\My Movies (e.g. \\LUX-1234\My Movies). When copying movies, DO NOT make a reference to the title via "D:\Movies", but link your titles to the \\[server name]\Movies instead of "D:\Movies" - when using the browse dialog, you can do this by browsing to your local network instead of your local files.
    • Edited by b_weeks Wednesday, August 12, 2009 11:44 PM
    Wednesday, August 12, 2009 11:40 PM