Topic: Processor upgrade

[vladd]

I have the following setup: SME 7.3 on an Athlon 64 3200+ (Gigabyte MB with 2x512MB of RAM and 3x500GB of HD) acting as network master, file server and VMware host for another SME 7.3 (512MB of allocated RAM) acting as mail server. I have some performance issues (slow response time in the WebMail for instance) and I'm considering upgrading the system's RAM (to minimize swapping from the VM) as well as upgrading the CPU to an Athlon 64 X2 (probably 5050e) so the VM won't step on the toes of the host when it comes to disk access.

Question(s): How would the SME react to changing a single core CPU with a dual core? Would I have to do any preparation (other than backup) or post-configuration to minimize the impact of such a change (I wouldn't like to reinstall SME)?

Thanks.

[CharlieBrady]

How would the SME react to changing a single core CPU with a dual core?

It would use the second core if you boot the SMP kernel. If you boot the uniprocessor kernel there will be no change other than speed.

[vladd]

Hi CharlieBrady,

Thanks a lot for the quick reply. I'd appreciate a "how to do that" or a pointer to such info, but only if it's simple for you (I think I can dig this info myself).

P.S. Any idea what's with this "You have made too many requests per second" message I'm getting when trying to access the forum (I'm not doing anything weird ...)?

[cactus]

Thanks a lot for the quick reply. I'd appreciate a "how to do that" or a pointer to such info, but only if it's simple for you (I think I can dig this info myself).

During boot up switch to the correct (SMP) kernel by pressing a key during the display of the splash screen.

P.S. Any idea what's with this "You have made too many requests per second" message I'm getting when trying to access the forum (I'm not doing anything weird ...)?

Were you perhaps downloading from contribs.org at the same time? Does your browser use some sort of prefetch mechanism?

[vladd]

Thanks for all the info. I think I figured out the remaining details.

I just have one more question related to my planned upgrade.

As mentioned in my original post, my 1TB disk space is made out of 3x500GB in RAID5; I could get to the same result with 2x1TB in RAID1.

Does anybody have any recent numbers on how big is the disk access penalty when using RAID5 over using RAID1? (1TB disks are not that expensive, but I don't know if the gain worths the cost).

[Stefano]

Does anybody have any recent numbers on how big is the disk access penalty when using RAID5 over using RAID1? (1TB disks are not that expensive, but I don't know if the gain worths the cost).

assuming you are using sw raid, with nowadays cpu you should not note the difference..

anyway, 1TB of data is a huge quantity: how do you plan to backup it?

[vladd]

assuming you are using sw raid, with nowadays cpu you should not note the difference..

Yes, I only meant the two RAID options implemented by SME. The thing is that in my current configuration (with only one CPU core), the guest SME (installed on one virtual disc with "nospare") is accessing the disk via VMware services, which in turn are using the host SME services to actually get to the hard drive. Those three layers seem to be stepping on eachother trying to get CPU time. That's why I was curious if there is any relevant RAID performance data available ...

1TB of data is a huge quantity: how do you plan to backup it?

Well, there are three types of data on this server:

• truly dynamic: this is the email repository and it resides in the guest SME. For this, from time to time I back up the whole virtual machine(one of the reasons for this setup). I'll probably should implement some sort of daily incremental backup (after the new spam is learned and eliminated) ...
• somewhat dynamic: this is made of personal and work documents/files; for those (but there aren't so many) the backup is implemented in the Winsows world;
• almost static: those are pictures, music, ISOs, software kits ... Basically those files are already backed up (DVD, USB HD) before they get to the server.

Does that make sense?

[versa]

To be honest looking at your set up why would you want to have a virtual version of sme to handle mail only.
I think you are making life hard on yourself, you might be better off with your "real" SME Server also handeling your mail, have a good back up solution, use vmware for testing or running a service that would take too much hacking of SME to run.

Which version of vmware are you running ?
I find V2 takes a bit out of life out of a virtual machine..
I find there is always a performance hit of some sort on any virtual machine unless you run a mother of a server.

Just a point of view....

[vladd]

To be honest looking at your set up why would you want to have a virtual version of sme to handle mail only.
I think you are making life hard on yourself, you might be better off with your "real" SME Server also handeling your mail

I found that the amount of explicit configuration required by setting up a mail server is quite extensive (users, pop3 accounts, filtering and forwarding rules, etc.). With the SME-in-VM setup I can restart this server on any other computer (Linux or Windows alike) either from backups (in case of a hardware crash of the server) or by copying the VM's files (in case of a major scheduled maintenance action, such as a hardware upgrade).

Which version of vmware are you running ?
I find V2 takes a bit out of life out of a virtual machine..

Yes, I was disappointed by V2 as well. I am using V1 and plan to experiment with VirtualBox (kernel permitting) ...

I find there is always a performance hit of some sort on any virtual machine unless you run a mother of a server.

The performance hit is obvious ... the question is if it is acceptable for a specific application. In my case, I evaluated that since the file server isn't actually doing much, the VM should run pretty smoothly. And that's true most of the time, so I decided I can live with the little performance annoyances.

Last week, however, a friend of mine did an experiment with a new i7 PC: using VirtualBox, he noticed that the boot time of a guest Windows XP that was given access to all the cores was waaay longer than if it was given access to only half of them. And that's how I understood the intensity of the fight for CPU between the guest and the host and I thought about upgrading my CPU to a dual core (while there still are AM2 CPUs out there).

[cirkit]

I remotely operate my server, How do i choose smp or normal kernel form putty or server-manager (remotely). (I have a dual processor server)

[cirkit]

I remotely operate my server, How do i choose smp or normal kernel form putty or server-manager (remotely). (I have a dual processor server)

[cactus]

I remotely operate my server, How do i choose smp or normal kernel form putty or server-manager (remotely). (I have a dual processor server)

Modify /etc/grub.conf and change the following line:

Code: [Select]

default=?Replace the question mark with the number of the entry of the kernel you desire minus one (as counts starts at 0), so if you want to start the second kernel you enter:

Code: [Select]

default=1You can decide which kernel you like by looking at the line that contains

Code: [Select]

kernel /vmlinuz ....
After you have saved your changes you can reboot your machine to load the new kernel:

Code: [Select]

signal-event reboot

[cirkit]

Thanks! I could choose between three kernels successfully.

[purvis]

Hey vladd

would you consider installing your ram first and giving us some tid bits of what you see. I suppose your going to put in 3 or 4 gig of ram.  Try for 4 and give the vm at least 1.5 gig.

Did you remove or add any services on the sme vm from the stock services.

Thank you

[vladd]

would you consider installing your ram first and giving us some tid bits of what you see. I suppose your going to put in 3 or 4 gig of ram.  Try for 4 and give the vm at least 1.5 gig.

Sure, no problem. My PC parts store would get the processor in about a week, and that's when I'll buy the RAM too. I'll install the RAM, let the system for a few days to see the effect and then I'll replace the CPU as well.

A note on the vm's performance: it was behaving way worse until I figured that VMware was set to allow the swapping of "some" of the vm's memory. At that time the vm had 256 MB of RAM and was swapping about 350 MB on the average (the host had 0 swapping). After I set VMware not to allow vm memory swapping and gave the vm 512 MB of RAM, the performance increase was significant. Now the vm is only swapping some 200 MB (but has more free memory) and the host is only swapping some 50 MB on the average. There still is some lack of responsiveness in the Web Mail (hence my desire to upgrade the hardware), but it is bearable.

Did you remove or add any services on the sme vm from the stock services.

Not explicitly ... but I've added some contribs ("system monitor" for instance) that I'm sure have installed/enabled more services compared to the default setup.