On Sun, Dec 22, 2013 at 11:57 PM, Eric Shubert <e...@shubes.net> wrote:
> Hey Kahn, > > First, I would try to avoid running anything other than the hypervisor on > bare iron. Run everything virtualized underneath it. > > Generally speaking, KVM performs better with newer kernels. Older kernels > use 10-20% of a cpu when idle. With newer kernels, KVMs use <0.5% cpu when > idle. > > I'm not sure exactly what the change is that provides this improvement. It > appears to have happened around 3.4 in the main kernel versions, but it > also appears that RedHat (and thus COS) has backported this change to their > 2.6.32 version. BL, COS6 runs well as a KVM, but COS5 does not. I expect > that both hypervisor and guests need to be running the improved version of > the kernel to realize this improvement. > > My virtualization platform of choice is ProxmoxVE. It provides a nice web > interface for management, and has been very reliable for me. I've used > versions 2.1-3.1. While PVE is debian based and uses .deb packages, it uses > a RedHat kernel, which give it the performance gains mentioned. > > The PVE kernel also provides OpenVZ container support, as does the web > interface. While COS5 guests don't run so well as KVMs, they run quite > nicely as OpenVZ containers. I won't go into the differences here, but > running just about anything linux based as an OpenVZ container should work > ok. > > I should emphasize that the point is not that running COS5 as a KVM > *won't* work (it will), it's just that there's some overhead involved > that's been eliminated in more recent kernels. In fact, I've run COS5 as > KVMs in production just fine for a period of time, on as little as a > dual-core 1.6GHz machine. It's fine so long as the horsepower's available > to run it (which it quite commonly is, as I've found most servers to be > severely overbuilt). > > The only thing that bothers me with PVE is that beginning with 3.1 (which > is the current release), they've introduced a subscription based structure > for their repos, sort of like RHEL. The cost isn't excessive for small > users, but it still rubs me the wrong way. They do still provide a free > repo, but all the latest changes aren't guaranteed to be there. We'll see > how things pan out in the long run. I wouldn't be surprised to see a > COS-type counterpart to PVE spring up and provide all of the PVE software > for free, only lagging slightly in when it's released. > > I should also probably mention that I started using virtualization with > VMware Server 1.0. After VMware discontinued VMware Server 2.0, I began > looking for something KVM based, and have been using PVE since then. I > realize that there is a free VMware version, but it's very limited to > certain enterprise grade hardware. I'm looking for something more > affordable that can run on generic hardware. VMware undoubtedly is the > leader in server virtualization, but RedHat is making substantial gains in > that arena. > > VirtualBox has grown up out of Desktop Virtualization. It's a very nice > platform for virtualizing desktops, and I consider them the leader in this > arena. Desktop virtualization has much different needs though, as desktops > are used much differently than servers. I don't look for VB to become a > substantial player in the server virtualization market. > > Let me know if you have any further questions. I hope we'll get this sort > of info available on the new wiki at github in the future. There is some > virtualization info on the present wiki, but it's pretty outdated. > > Thanks for the questions. > > -- > -Eric 'shubes' > > > On 12/22/2013 12:23 AM, Khan Mohamed Ashraf wrote: > >> On Sat, Dec 21, 2013 at 9:52 PM, Eric Shubert <e...@shubes.net >> <mailto:e...@shubes.net>>wrote: >> >> >> On 12/20/2013 08:48 PM, Biju Jose wrote: >> >> You may want have a look at >> http://www.webtatic.com/__packages/php53/ >> >> <http://www.webtatic.com/packages/php53/> >> >> *Biju Jose* >> >> Pplease consider the environment before printing this e-mail. >> >> *From:*Chandran Manikandan [mailto:tech2m...@gmail.com >> <mailto:tech2m...@gmail.com>] >> *Sent:* Saturday, December 21, 2013 7:14 AM >> *To:* qmailtoaster-list@__qmailtoaster.com >> <mailto:qmailtoaster-list@qmailtoaster.com> >> >> *Subject:* [qmailtoaster] How to update PHP higher version without >> >> affect qmailtoaster >> >> Dear All, >> >> I am running centos 5.7 with qmailtoaster + dovecot and don't >> have any >> issue. >> >> My PHP is 5.1 version. >> >> I would like to install wordpress with php 5.2 or higher version >> compatible. >> >> If i try to update php53 or higher version it's >> squirrelmail,qmailadmin,__vqadmin toasters affected and removed. >> >> >> Could you please anyone help me to solve this issue without affect >> qmailtoaster need to be update php updated version. >> >> -- >> >> *Thanks,* >> >> *Manikandan.C* >> >> *System Administrator* >> >> >> I haven't put php5.3 on COS5, but I've heard that it can be done. >> >> That being said, if you're not in a big hurry for WP, you might wait >> for the next QMT on COS6. That's presently in active testing, and I >> expect to be production worthy early next year (within a few weeks). >> >> That being said, I would caution against putting too many eggs in >> one basket. With all that running on a single host, you should give >> virtualization strong consideration. If you were already running on >> a virtual platform, you wouldn't be asking this question. You could >> simply dedicate a VM to WP, and things would run happily together. >> >> Also, are you really sure you want to end up with WP and vpopmail >> databases in the same mysql instance? Virtualization also makes >> avoiding this easy. Of course, you can still put them together in >> the same mysql instance if you'd like. >> >> Bottom Line, virtualization gives you a lot of flexibility you don't >> have with bare iron installs. Of course, it's up to you. >> >> -- >> -Eric 'shubes' >> >> >> ------------------------------__---------------------------- >> --__--------- >> To unsubscribe, e-mail: >> qmailtoaster-list-unsubscribe@__qmailtoaster.com >> <mailto:qmailtoaster-list-unsubscr...@qmailtoaster.com> >> For additional commands, e-mail: >> qmailtoaster-list-help@__qmailtoaster.com >> <mailto:qmailtoaster-list-h...@qmailtoaster.com> >> >> >> >> Eric, >> >> I need some advice. >> At the top of year I had a existing install of CentOS 5.9 running QMT. >> I needed to run a webserver which required CentOS 6 >> I ran into problems with the performance of CentOS 6 running in >> a VirtualBox VM on the CentOS 5.9 install. >> Would it have been better to run CentOS 6 on metal and virtualise CentOS >> 5.9? >> Is it the recommended way, to virtualise earlier versions rather than >> run later versions >> on VM's in older OS versions. >> I also need your opinion on VirtualBox as a virtualisation environment. >> Thanks >> >> Ashraf >> >> >> -- >> Khan Md. Ashraf >> First Floor, >> New #8 Old #12, >> 9th Cross Street, Shastrinagar, >> Chennai 600 020 >> India >> Tel: 91 44 24462713, 43018713, 42029358 >> Mobile: 91 9841032607 >> > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: qmailtoaster-list-unsubscr...@qmailtoaster.com > For additional commands, e-mail: qmailtoaster-list-h...@qmailtoaster.com > > Eric, Thanks a ton for that tremendous insight into server virtualisation. I sure am glad I asked you the question. Once again I must say that the QMT project run by you and formerly Jake Vickers has done unreserved yeoman service to the idea of a common global humanity. And I for one will be forever grateful for that. Ashraf -- Khan Md. Ashraf First Floor, New #8 Old #12, 9th Cross Street, Shastrinagar, Chennai 600 020 India Tel: 91 44 24462713, 43018713, 42029358 Mobile: 91 9841032607
