Why do my dom0s have only 600MB RAM?
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I am certain the default is supposed to be 752MB on 6.x
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Linux tends to get lighter with each generation and making the Dom0 lighter was a big push in XS7. That's probably correct, less memory is needed this generation.
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Im still on 6.5 sp1 in production though.
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@momurda said in Why do my dom0s have only 600MB RAM?:
Im still on 6.5 sp1 in production though.
Oh... and that's all that it assigned? That's odd. Have you exhausted the memory for the VMs?
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Thats what i am wondering. this morning, doing a heavy file IO since last night i got the dreaded
SR_BACKEND_FAILURE error 47 on one host, which used to happen a lot when i first started. I thought i had this one fixed after replacing a mobo and adding Ram to hosts.Theonly way for this to happen is to manually change the amount within the XS cli correct?
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I believe that that is correct.
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From my limited Xen knowledge dom0 is essential for stable Xenserver performance, esp for file io. Why the hell would anyone ever lower that amount? To make me angry 2 years later? They never even met me... To save a hundred dollars instead of buying ram?
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@momurda said in Why do my dom0s have only 600MB RAM?:
From my limited Xen knowledge dom0 is essential for stable Xenserver performance, esp for file io. Why the hell would anyone ever lower that amount? To make me angry 2 years later? They never even met me... To save a hundred dollars instead of buying ram?
How much RAM are your VMs taking up?
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They all have fixed ram amounts mostly 2-8gb. Total mem usage on each host is way less than the 128GB available to each host. Yet dom0 memory allocation was reduced in size at some point in the past by 20%.
Ridiculous. though it could have been a step someone, who worked here in the past, took when these hosts only had 32GB ram each and had the same # of vms.(25-30)
edit: clarity -
Oh, I see, someone who works there might have reduced them at some point. Now I see. Yes, expand those a bit
@DustinB3403 how much memory does your Dom0 have?
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@scottalanmiller said
@DustinB3403 how much memory does your Dom0 have?
Oh, what? You can't ask me?
Probably for the best since I don't know how to check.
See me in 2017.
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@BRRABill said in Why do my dom0s have only 600MB RAM?:
@scottalanmiller said
@DustinB3403 how much memory does your Dom0 have?
Oh, what? You can't ask me?
Probably for the best since I don't know how to check.
See me in 2017.
free -m
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Discrete systems.
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Here is my least powerful system.
This host has 8GB of RAM (really 7167 MB) and dom0 is using 1015 MB
My host from have 65513 MB total, and 3134 MB to dom0 and 98210 MB and 5577 MB to dom0 respectively.
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@DustinB3403 said in Why do my dom0s have only 600MB RAM?:
Here is my least powerful system.
This host has 8GB of RAM (really 7167 MB) and dom0 is using 1015 MB
My host from have 65513 MB total, and 3134 MB to dom0 and 98210 MB and 5577 MB to dom0 respectively.
Looks like it only has 596MB.
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Correct, it does for the least powerful of my servers. This unit only has 8GB of ram in it.
But was a simple straight install of XS 6.5
So the installation possibly scales the memory for Dom0 based on the hardware it finds present.
@momurda how much memory does this host have?
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Yes, it should be scaling based on the memory in the system.
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Lack of Ram, not a problem. Each host has 128GB. someone forced the hosts to use 608MB. I changed them last night per Citrix document, but set it to use 3G. See if that solves the problem. Was hitting less than 20MB free during normal operations, that is bad. Now it is not.
http://support.citrix.com/article/CTX134951 --should be using between 1024 MB and 4096 MB.per
Instructions
To configure the dom0 memory, complete the following procedure:On the XenServer host, open a local shell and log on as root.
Enter the following command:
/opt/xensource/libexec/xen-cmdline --set-xen dom0_mem=<nn>M,max:<nn>M
Note: <nn> represents the memory in megabytes, to be allocated to dom0. This value should be between 1024 and 4096, depending on the number of VMs that are expected to run and the total memory of the host. A higher value results in less memory being available to the VMs.Example : /opt/xensource/libexec/xen-cmdline --set-xen dom0_mem=4096M,max:4096M
Note: The above command will set the dom0 memory to 4GB or 4096 MB.
User-added imageReboot the XenServer host using XenCenter or reboot command on the console.
After the host is rebooted, run the command free on the console to verify the new memory settings. -
@momurda said in Why do my dom0s have only 600MB RAM?:
Lack of Ram, not a problem. Each host has 128GB. someone forced the hosts to use 608MB. I changed them last night per Citrix document, but set it to use 3G. See if that solves the problem. Was hitting less than 20MB free during normal operations, that is bad. Now it is not.
So someone customized the installation on this host to use a custom amount of RAM?
Time to get out Mr. Slappy (left and right hands and slap that person)
