Solved Get Large Disk Images on XenServer 6.5 on Local Filesystem?
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@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@scottalanmiller said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
So while driving and quickly reading through this, I found this. https://community.spiceworks.com/topic/394390-citrix-xenserver-6-2-local-storage-2tb-limit
Looks like changing to GUID might allow more space.
If u misunderstood what you were saying, sorry I'm driving.
The limitation is not the size of the SR but the size of the VHDs that you can create on top of it.
Ah ok. This person says it's because of a limit on Microsofts VHD format. https://joetutorials.wordpress.com/2015/06/03/how-to-create-virtual-disks-greater-than-2gb-in-xenserver/
Is there any way to use a raw LV instead of a VHD?
Yes, you can bypass the VHD format. But that's a crappy approach. Getting XS to create a VHDX would be so much better.
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@scottalanmiller said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@scottalanmiller said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
So while driving and quickly reading through this, I found this. https://community.spiceworks.com/topic/394390-citrix-xenserver-6-2-local-storage-2tb-limit
Looks like changing to GUID might allow more space.
If u misunderstood what you were saying, sorry I'm driving.
The limitation is not the size of the SR but the size of the VHDs that you can create on top of it.
Ah ok. This person says it's because of a limit on Microsofts VHD format. https://joetutorials.wordpress.com/2015/06/03/how-to-create-virtual-disks-greater-than-2gb-in-xenserver/
Is there any way to use a raw LV instead of a VHD?
Yes, you can bypass the VHD format. But that's a crappy approach. Getting XS to create a VHDX would be so much better.
Agreed. If you need to have it though, you could get the same functions with LVM, just would take some manual work.
But that sucks. I wonder why they chose VHD vs something like qcow2 which has a limit of like 9 million TBs.
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@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@scottalanmiller said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@scottalanmiller said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@johnhooks said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
So while driving and quickly reading through this, I found this. https://community.spiceworks.com/topic/394390-citrix-xenserver-6-2-local-storage-2tb-limit
Looks like changing to GUID might allow more space.
If u misunderstood what you were saying, sorry I'm driving.
The limitation is not the size of the SR but the size of the VHDs that you can create on top of it.
Ah ok. This person says it's because of a limit on Microsofts VHD format. https://joetutorials.wordpress.com/2015/06/03/how-to-create-virtual-disks-greater-than-2gb-in-xenserver/
Is there any way to use a raw LV instead of a VHD?
Yes, you can bypass the VHD format. But that's a crappy approach. Getting XS to create a VHDX would be so much better.
Agreed. If you need to have it though, you could get the same functions with LVM, just would take some manual work.
But that sucks. I wonder why they chose VHD vs something like qcow2 which has a limit of like 9 million TBs.
I wonder that too, since Xen supports it. It is an XS limitation, not an Xen one.
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@scottalanmiller Here's a recent discussion from the Citrix forums that addresses this topic.
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@This - driving me crazy!. As we're looking to move to localized server/storage and AWAY from a NAS setup external storage.
So, attach 2TB disk to the Virtual Machine within XenServer. its 2TB limit due to Microsoft VHD limitations....
So, say we're attaching this 2TB disk to a Windows Server VM..... be limited as far as storage needs go. In our usage case, this would be for Employee profiles / save data. I see this being an issue in the long run.
Only way around, would be to setup a NFS share or SMB share and attach it as a network drive to the Guest Operating system and or GPO policy to map this network share to employee's to save data.
Then you're still including a network level SAN/external storage.... which is single point of failure.
@scottalanmiller always beats us up on having SAN/External storage. Unless ofcourse has split controllers / arrays for redundancy. I would love to have me a EMC VNXe..
EDIT: beats us up over the fact of single point of failure, or more than one point of failure by introducing server + external network storage. As if network storage device goes down, lose your Storage Repository.
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@ntoxicator The issue here (does present a single point of failure) but only for the storage device.
Sure if that device dies that storage is offline, but the VM is still usable. So it's a Storage SPOF, rather than a System SPOF.
I'd rather have a Storage SPOF (in this case) than a System SPOF if I had the choice. Which to alleviate this SPOF you'd get a good NAS/SAN and use that.
Not a unreliable piece of garbage.
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Understood!
But then the scenerio comes back full circle, as when you're not maintaining the SMB shares FROM windows server. your networked storage device sharing out NFS/SMB will have to do AD-integration for user authentication to carry out the NTFS read/write permissions?
Typically do Share = Everyone. NTFS Permissions = by group/user.
I make my head spin with all the scenario's. As I myself am in a data situation.
EDIT: I realize that if i do a SMB share from a network storage, the actual file system does not need to be NTFS, can be say EXT4, as long as using SMB protocal. Windows devices and even Mac will see it and can read/write data. Its just the fact of allowing the appropriate and proper control on who/what has access to that share for read/write
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My question is this; How often do you need a 2TB minus 4GB share as a single partition for SMB / NFS services?
What use case is @scottalanmiller looking at where he is trying to find a solution to this?
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
My question is this; How often do you need a 2TB minus 4GB share as a single partition for SMB / NFS services?
What use case is @scottalanmiller looking at where he is trying to find a solution to this?
Often if you are making a file server. Really, really often, actually.
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@scottalanmiller But why not make a file server with several vDisk rather than a massive disk?
What are the benefits?
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@ntoxicator The issue here (does present a single point of failure) but only for the storage device.
Sure if that device dies that storage is offline, but the VM is still usable. So it's a Storage SPOF, rather than a System SPOF.
I'd rather have a Storage SPOF (in this case) than a System SPOF if I had the choice. Which to alleviate this SPOF you'd get a good NAS/SAN and use that.
Not a unreliable piece of garbage.
What's the difference in SPOF, though, either one fails your services are down. Total outage either way.
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I disagree, you have an outage of a single storage platform. If everything is hosted from this external storage, sure then it could be a complete outage.
But you'd still have access to the VM to manage / repair whatever is broken at the VM level (if anything).
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
I disagree, you have an outage of a single storage platform. If everything is hosted from this external storage, sure then it could be a complete outage.
But you'd still have access to the VM to manage / repair whatever is broken at the VM level (if anything).
So specifically in a case where you have storage that isn't important? Sure, like if you are mounting a backup share and are happy losing it. Certainly doesn't apply to any normal use case. If your database vanishes from your database server, "fixing" the VM is pointless. If the storage is gone from your file server, keeping it up and running is pointless.
What scenario did you have in mind?
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@scottalanmiller I'm just trying to think of a scenario where you need to have a larger than 2TB partition for file services. (I haven't seen any in my experience - don't take that as me saying they don't exist).
Which if you need a larger partition, the current solution is external storage to the Hypervisor (yes it sucks for all of the reasons mentioned and going through your head).
The only cases that I could imagine this as being used would be if you wanted to attach an device to a VM for backup purposes, which then get pushed off. Massive "localish" storage for the VM to quickly replicate from the proper shares to the iSCSI device.
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
@scottalanmiller I'm just trying to think of a scenario where you need to have a larger than 2TB partition for file services.
This is super common for a business of any size. Pretty much, if you have 2TB of files, you have run into this scenario.
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Other than tiny file servers, what situations can you imagine where a single large partition is not desired? Try it in reverse. You seem to think this is uncommon, but in reality, I think it's the standard case.
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I've seen far more smaller partitions (2TB and under) shared out than I've seen massive (+2TB) shares configured and setup. .
The burden to provide examples isn't on me, but on you @scottalanmiller.
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@scottalanmiller I work in about the smallest environment it's possible to still have IT, and only because 5 different companies are actually under the same ownership. Even I'm looking at that 2TB cap saying, that's just not enough!
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
I've seen far more smaller partitions (2TB and under) shared out than I've seen massive (+2TB) shares configured and setup. .
The burden to provide examples isn't on me, but on you @scottalanmiller.
We have home directories that mount from multiple servers that have 52 TB a piece.
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@DustinB3403 said in Get Large Disk Images on XenServer 6.5 on Local Filesystem?:
I've seen far more smaller partitions (2TB and under) shared out than I've seen massive (+2TB) shares configured and setup. .
The burden to provide examples isn't on me, but on you @scottalanmiller.
Not really, I asked for an industry standard, you are saying that it's not a real use case. Since just about every company of any size is looking at scores or hundreds of TB of storage (or PB even), saying that 2TB is a reasonable upper bounds needs some explaining. Why would this be? Other than very tiny companies or those with very tiny storage needs, when would so little storage capacity make sense?
Considering none of my storage units at home are this small, not even from six years ago or more, this makes no sense to me. From a size perspective, this is below the home line in many cases... just storing music, home movies and such often requires far more than this (I have about 12TB for home.)
