I''m looking at using Xen to host our client''s servers and I was trying to determine how Xen would scale and how many machines I should expect to be able to run. I am currently running Xen 3 on a FC4 test box and have a couple of test machines running. I really like it so far and after some stress testing we''re going to invest in some more advanced hardware. What processors would you recommend? I was thinking of dual core opterons, but I wasn''t sure if Xen would work well on Opterons and take advantage of the Dual core processor. Does Xen 3 still suffer from a 4GB RAM limit? Has anyone had any experience with the newer SATA solutions versus SCSI disk? I''m thinking of a SATA RAID 5 setup to save some cash and gain some needed space. What seems to work better, running from an image file or setting up each host to use a partition? I like the simplicity of an image file, but an lvm partition would be nice because you can resize them on the fly. Thanks, Eric _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Charles Duffy
2005-Dec-22 16:21 UTC
[Xen-users] Re: What hardware should I be considering?
Eric Peterson wrote:> I was thinking of dual core > opterons, but I wasn''t sure if Xen would work well on Opterons and take > advantage of the Dual core processor.It does.> Does Xen 3 still suffer from a 4GB RAM limit?No.> Has anyone had any experience with the newer SATA solutions versus SCSI > disk? I''m thinking of a SATA RAID 5 setup to save some cash and gain > some needed space.I''m using 3ware''s 9000-series controllers, and they work for me, but I''m thinking of trying some of Areca''s units when I get the opportunity.> What seems to work better, running from an image file or setting up each > host to use a partition? I like the simplicity of an image file, but an > lvm partition would be nice because you can resize them on the fly.I strongly prefer using LVM devices -- better performance, and some things (like GFS) don''t work via loopback. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Petersson, Mats
2005-Dec-22 16:39 UTC
RE: [Xen-users] What hardware should I be considering?
Xen 3 with PAE or in 64-bit mode will allow you to use > 4GB RAM (2 ^ 36 = 16 GB in PAE and 2 ^ 40 = 1024 GB of physical memory in 64-bit mode). It will use Dual core processors just fine - Xen 3 supports a fairly large number of processors, I think someone was trying out a 64 CPU machine a few months back. I don''t know much about SATA vs. SCSI RAID, I''m using SATA in a single disk mode on one of my machines here and it works just fine - but that''s just a single disk and just "happens" to be SATA because that''s the disk the machine came with - not by my choice, just what it happened to have. Certainly a lot cheaper to use SATA or IDE disks if you want lots of space ;-) As to file/LVM, it does depend a lot on what your target would be and how often for instance you need to resize your partitions. -- Mats ________________________________ From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Eric Peterson Sent: 22 December 2005 15:48 To: Xen-users@lists.xensource.com Subject: [Xen-users] What hardware should I be considering? I''m looking at using Xen to host our client''s servers and I was trying to determine how Xen would scale and how many machines I should expect to be able to run. I am currently running Xen 3 on a FC4 test box and have a couple of test machines running. I really like it so far and after some stress testing we''re going to invest in some more advanced hardware. What processors would you recommend? I was thinking of dual core opterons, but I wasn''t sure if Xen would work well on Opterons and take advantage of the Dual core processor. Does Xen 3 still suffer from a 4GB RAM limit? Has anyone had any experience with the newer SATA solutions versus SCSI disk? I''m thinking of a SATA RAID 5 setup to save some cash and gain some needed space. What seems to work better, running from an image file or setting up each host to use a partition? I like the simplicity of an image file, but an lvm partition would be nice because you can resize them on the fly. Thanks, Eric _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Eric Peterson
2005-Dec-22 22:07 UTC
Re: [Xen-users] What hardware should I be considering?
Thanks for all the info. Good to know about the memory support and processor support. The more I use Xen the more I love it. My next question relates to GFS. I haven''t searched much regarding Xen and FC4 so please don''t flame me on it. I do see there are GFS kernel rpms for Xen using Fedora. I used the install script (xen-install-fc4) that xensource provides and use the 2.6.12.6-xen3_2.1_fc4 kernel version for both dom0 and domU. I don''t suppose this also has GFS support built into it? Anyone else using GFS and Xen? Seems like a great way for redundancy and failover services. I''ll search the archives, but thought maybe someone would like to post their experience with both of them. Thanks again. Eric On 12/22/05, Petersson, Mats <mats.petersson@amd.com> wrote:> > Xen 3 with PAE or in 64-bit mode will allow you to use > 4GB RAM (2 ^ 36 > 16 GB in PAE and 2 ^ 40 = 1024 GB of physical memory in 64-bit mode). > > It will use Dual core processors just fine - Xen 3 supports a fairly large > number of processors, I think someone was trying out a 64 CPU machine a few > months back. > > I don''t know much about SATA vs. SCSI RAID, I''m using SATA in a single > disk mode on one of my machines here and it works just fine - but that''s > just a single disk and just "happens" to be SATA because that''s the disk the > machine came with - not by my choice, just what it happened to have. > Certainly a lot cheaper to use SATA or IDE disks if you want lots of space > ;-) > > As to file/LVM, it does depend a lot on what your target would be and how > often for instance you need to resize your partitions. > > -- > Mats > > ------------------------------ > *From:* xen-users-bounces@lists.xensource.com [mailto: > xen-users-bounces@lists.xensource.com] *On Behalf Of *Eric Peterson > *Sent:* 22 December 2005 15:48 > *To:* Xen-users@lists.xensource.com > *Subject:* [Xen-users] What hardware should I be considering? > > I''m looking at using Xen to host our client''s servers and I was trying to > determine how Xen would scale and how many machines I should expect to be > able to run. > > I am currently running Xen 3 on a FC4 test box and have a couple of test > machines running. I really like it so far and after some stress testing > we''re going to invest in some more advanced hardware. > > What processors would you recommend? I was thinking of dual core > opterons, but I wasn''t sure if Xen would work well on Opterons and take > advantage of the Dual core processor. > > Does Xen 3 still suffer from a 4GB RAM limit? > > Has anyone had any experience with the newer SATA solutions versus SCSI > disk? I''m thinking of a SATA RAID 5 setup to save some cash and gain some > needed space. > > What seems to work better, running from an image file or setting up each > host to use a partition? I like the simplicity of an image file, but an lvm > partition would be nice because you can resize them on the fly. > > Thanks, > Eric > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users