List:
I am considering getting a Xen based virtual server for providing static web-site, secondary MX & DNS. Pros & Cons? anyone?
Minimal install from the centos server CD (centos will be the guest OS) with Apache, Selinux, Iptables, qmail, spamassasin, djbdns, clam, mysql, postgreSQL & INN. Any install issues?
What should be the HDD & RAM requirement, in addition to my database size & say 10 GB for mail?
Also, how much bandwidth saving can I get with say 10 MB mail (from mailing lists) and script to compress and get it by rsync?
Secondly, is it possible to compress news server feed & batch download in compressed format, reliably. I am trying to save on extra bandwidth costs here in India.
Also, can someone recommend and Xen Virtual host provider on my direct email address...anyone who is small & can do a bit of hand-holding initially...without a big dollar denominated bill ;-) Small shoestring budget..a very very small shoestring ;-)
With best regards.
On 12/1/05, Sanjay Arora sanjay.k.arora@gmail.com wrote:
List:
I am considering getting a Xen based virtual server for providing static web-site, secondary MX & DNS. Pros & Cons? anyone?
Minimal install from the centos server CD (centos will be the guest OS) with Apache, Selinux, Iptables, qmail, spamassasin, djbdns, clam, mysql, postgreSQL & INN. Any install issues?
What should be the HDD & RAM requirement, in addition to my database size & say 10 GB for mail?
Also, how much bandwidth saving can I get with say 10 MB mail (from mailing lists) and script to compress and get it by rsync?
Secondly, is it possible to compress news server feed & batch download in compressed format, reliably. I am trying to save on extra bandwidth costs here in India.
Also, can someone recommend and Xen Virtual host provider on my direct email address...anyone who is small & can do a bit of hand-holding initially...without a big dollar denominated bill ;-) Small shoestring budget..a very very small shoestring ;-)
I wouldn't call myself an expert, but...
With everything I've read and researched, prior to this, I've come to the conclusion that this would take a considerable amount of time and effort. The resulting installed system would only vaguely resemble CentOS on the surface. Would require a non-standard, most likely self created and maintained, repository for yum updates.
IIRC this would require patching and recompiling the kernel, newer gcc and recompiling a significant number of other binaries...
Maybe you could call the new distro XentOS.
Please correct any errors of misconceptions I have.
-- Leonard Isham, CISSP Ostendo non ostento.
On 12/1/05, Leonard Isham leonard.isham@gmail.com wrote:
With everything I've read and researched, prior to this, I've come to the conclusion that this would take a considerable amount of time and effort. The resulting installed system would only vaguely resemble CentOS on the surface. Would require a non-standard, most likely self created and maintained, repository for yum updates.
IIRC this would require patching and recompiling the kernel, newer gcc and recompiling a significant number of other binaries...
Actually, I was able to get CentOS running under Xen (as host and guest) without too much effort. Unfortunately, I didn't take very good notes... No custom repository or newer gcc or other recompiling is needed. A patched kernel is needed, but Xen automates that for you; see Xen's docs for details.
Xen's web site provides a binary download of Xen 2.0.7, which works without any problems, although their precompiled kernel (based off of a stock 2.6.x kernel) contains relatively few modules. You can also recompile 2.0.7 from source to add kernel modules. Getting Xen 2.x to work with CentOS's customized kernel, or getting Fedora's newer version of Xen to work, could be quite a bit more effort.
Since you haven't updated glibc, you'll want to mv /lib/tls /lib/tls.disabled on both host and guest OSes to improve performance. Installing the guest OS can be a bit trickier; you can do a CD-based install (reboot the host off of the CD then install CentOS to an blank partition that will be used as the guest), or you can use rpmstrap or yum --installroot. See http://mark.foster.cc/wiki/index.php/Centos-4_on_Xen for details on the latter two options.
Feel free to contact me if you have any more questions. Hope this helps.
Josh Kelley
Josh Kelley wrote:
Actually, I was able to get CentOS running under Xen (as host and guest) without too much effort. Unfortunately, I didn't take very good notes... No custom repository or newer gcc or other recompiling is needed. A patched kernel is needed, but Xen automates that for you; see Xen's docs for details.
Xen's web site provides a binary download of Xen 2.0.7, which works without any problems, although their precompiled kernel (based off of a stock 2.6.x kernel) contains relatively few modules. You can also recompile 2.0.7 from source to add kernel modules. Getting Xen 2.x to work with CentOS's customized kernel, or getting Fedora's newer version of Xen to work, could be quite a bit more effort.
Since you haven't updated glibc, you'll want to mv /lib/tls /lib/tls.disabled on both host and guest OSes to improve performance. Installing the guest OS can be a bit trickier; you can do a CD-based install (reboot the host off of the CD then install CentOS to an blank partition that will be used as the guest), or you can use rpmstrap or yum --installroot. See http://mark.foster.cc/wiki/index.php/Centos-4_on_Xen for details on the latter two options.
Feel free to contact me if you have any more questions. Hope this helps.
Josh Kelley
I'm using Centos as my host and guest operating systems.
The big thing that didn't work out of the box for me was firewalling so I compiled my own Xen kernel (only minor heavy lifting required) http://www.pendragon.org/mywiki/Xen
If TLS is absolutely required glibc would have to be recompiled with the appropriate flag: -mno-tls-direct-seg-refs http://wiki.xensource.com/xenwiki/XenSpecificGlibc
You can also install guests using something like: mount /dev/vg00/xen00 /mnt/tmp yum --installroot=/mnt/tmp -y groupinstall base umount /mnt/tmp
You will likely want to create a local repository out of the install media first though instead of installing all the rpms off of the 'net each time.
-Mike
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Josh Kelley -
Leonard Isham -
Michael Best -
Sanjay Arora