Hi Guys,
Please forget the "thousands" number. We would have thousands of DomUs, but this would be spread over multiple storage servers, so never mind about that scale.
If I was exporting "One big LUN" per Xen node, it would contain at most 80 DomU LVs (In real world usage, closer to 50). Furthermore, each LUN would be exported from a seperate RAID array. Each storage server would contain x number of RAID arrays, where x equals the number of Xen nodes and the number of exported LUNs.
Of course, if I went with one LUN per DomU, then each storage server would contain 80x LUNs (closer to 50x though).
With these numbers, any idea which is better?
Thanks
-----Original Message-----
From: Bart Coninckx [mailto:bart.coninckx@xxxxxxxxxx]
Sent: Sun 24/04/2011 19:36
To: Jonathan Tripathy
Cc: Jonathan Dye; Xen List
Subject: Re: [Xen-users] Shared Storage
That is completely dependent on your hardware specs and DomU's properties.
It sounds like a lot though. I seem to remember some time ago you also
stated to want to run at least 100 DomUs on one hypervisor, maybe this
is again pushing it.
With a decent RAID and 10gbit or infiniband you can go a long way
though. You should also consider using SCST instrad of IET as it is faster.
B.
On 04/24/11 20:31, Jonathan Tripathy wrote:
> We're talking houndreds, if not thousands of DomUs here. Will iSCSI on
> Linux scale to these large numbers?
>
> Thanks
>
>
> On 24/04/2011 19:13, Jonathan Dye wrote:
>> Why not create one iscsi lun per vm disk instead of carving them up on
>> the hypervisor? That's more typical, and a more typical state of
>> affairs in linux is your friend. Also, you would have just one lun
>> queue if you exported one big PV, instead of one lun queue per vbd.
>> That becomes a problem at scale.
>>
>> - Jonathan
>>
>> ----- Original Message -----
>> From: "Jonathan Tripathy"<jonnyt@xxxxxxxxxxx>
>> To: "Xen List"<xen-users@xxxxxxxxxxxxxxxxxxx>
>> Sent: Sunday, April 24, 2011 11:25:38 AM
>> Subject: [Xen-users] Shared Storage
>>
>> Hi Everyone,
>>
>> I am consider such a setup where I export an iSCSI target to a Xen node.
>> This Xen node will then use the iSCSI block device as an LVM PV, and
>> create lots of LVs for DomU use.
>>
>> I was wondering if anyone could make me aware of any special
>> consideration I would need to take. I've posted a similar question to
>> the LVM list to ask for further tips more specific to LVM.
>>
>> Am I barking down the wrong path here? I know it would be very easy to
>> just an NFS server and use image files, but this will be for a large
>> scale DomU hosting so this isn't really an option. Additionally, if I
>> wanted to make the LVM VG visible to multiple Xen nodes, is it just a
>> matter of running CLVM on each Xen node? Please keep in mind that only
>> one Xen node will be using an LV at any one time (so no need for GFS, I
>> believe)
>>
>> Any help or tips would be appreciated
>>
>> Thanks
>>
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>
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