Hey All, I’m attempting to gather stats on usage of the “metal”, by which I mean the physical host’s hardware. I would like to know the CPU, IO, and network stats for the hardware. Normally I would get these from /proc/stat, /proc/diskstat, and ifconfig respectively. However, because of the segregation of VMs and Dom0’s special relationship as a paravirtualized I don’t know if I can trust this data. I’m aware that /proc/stat is unusable as Dom0 will not see cycles that DomUs are stealing, and thus it does not give me accurate utilization of the metal – I know that I can calculate the actual CPU usage of each VM using “vm list –long” and comparing cpu_time to uptime, so that’s not a problem. The issue arises when I attempt to get IO stats – DomUs see their own ‘sda1’ (or whichever) – I don’t know if this means that the ‘sda’ that Dom0 sees is the real hardware or an abstraction. The question I have is: do IO operations on DomUs result in IO operations on Dom0’s ‘sda’ such that /proc/diskstat sees it? Or is that hidden from Dom0 like DomU CPU usage? Similarly with network stats: I’m sure that Dom0’s eth0 does not report network traffic that DomUs used, but does peth0 report traffic that ‘hit the wire’? Additionally, does this include traffic that occurs between Dom0 and DomU, that doesn’t escape into the network substrate? I’m testing this myself as I write this, but I’d rather have my “research” confirmed by knowledgeable users. Thanks all, -Tyler Szabo _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hey All, I’m attempting to gather stats on usage of the “metal”, by which I mean the physical host’s hardware. I would like to know the CPU, IO, and network stats for the hardware. Normally I would get these from /proc/stat, /proc/diskstat, and ifconfig respectively. However, because of the segregation of VMs and Dom0’s special relationship as a paravirtualized I don’t know if I can trust this data. I’m aware that /proc/stat is unusable as Dom0 will not see cycles that DomUs are stealing, and thus it does not give me accurate utilization of the metal – I know that I can calculate the actual CPU usage of each VM using “vm list –long” and comparing cpu_time to uptime, so that’s not a problem. The issue arises when I attempt to get IO stats – DomUs see their own ‘sda1’ (or whichever) – I don’t know if this means that the ‘sda’ that Dom0 sees is the real hardware or an abstraction. The question I have is: do IO operations on DomUs result in IO operations on Dom0’s ‘sda’ such that /proc/diskstat sees it? Or is that hidden from Dom0 like DomU CPU usage? Similarly with network stats: I’m sure that Dom0’s eth0 does not report network traffic that DomUs used, but does peth0 report traffic that ‘hit the wire’? Additionally, does this include traffic that occurs between Dom0 and DomU, that doesn’t escape into the network substrate? I’m testing this myself as I write this, but I’d rather have my “research” confirmed by knowledgeable users. Thanks all, -Tyler Szabo P.S: Sorry for potential doublepost, I didn''t join the list before posting (from this account) before I posted ;) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Jun 11, 2009 at 5:10 PM, Tyler Szabo <tyler.szabo@gmail.com> wrote:> > The issue arises when I attempt to get IO stats – DomUs see their own ‘sda1’ (or whichever) – I don’t know if this means that the ‘sda’ that Dom0 sees is the real hardware or an abstraction. The question I have is: do IO operations on DomUs result in IO operations on Dom0’s ‘sda’ such that /proc/diskstat sees it? Or is that hidden from Dom0 like DomU CPU usage?All DomU''s IO passes through Dom0. there you can measure all you want. for disk IO, if you use phy: devices, you can use iostat to see the usage of each device. if you use file-based backends, it would be easier to check the userspace daemons. maybe iotop would help. in any case, if aggregate usage is all you need, just measure the disk usage seen at Dom0 for network, if you can measure at peth0, that would give you the aggregate usage. if you need stats for each DomU, check the respective tun devices. -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Fri, Jun 12, 2009 at 5:10 AM, Tyler Szabo<tyler.szabo@gmail.com> wrote:> Hey All, > > I’m attempting to gather stats on usage of the “metal”, by which I mean the > physical host’s hardware. I would like to know the CPU, IO, and network > stats for the hardware.I''d suggest you start with this thread http://lists.xensource.com/archives/html/xen-users/2009-05/msg00562.html In short, using values from xentop and Cacti, you can get disk and network throughput (for PV domU and HVM with PV drivers only) plus CPU time spent for dom0 and all domUs. -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users