yf chu
2021-Mar-05 07:54 UTC
[CentOS] Disk read io very high, but no process perform io read
We have experienced a very weird problem. The load of the server machine is very high. We use "pidstat" and find that the disk read io is very high. But the processes running on this server do not perform any disk read operation. We also noticed that when we execute "top" command, for most of processes, the values in "SHR" column are zero. Compared with other normal servers, we found that by executing "free -m", the result shows that the buff/cache value in this server is lower than the value of other normal servers. We also found that there were lots of major page faults by executing "ps -o majflt,minflt". Swap is not enabled on this server. What could be the reason for this issue? The centos version:CentOS Linux release 7.3.1611 kernel version:3.10.0-693.21.1.std7a.el7.0.x86_64
Simon Matter
2021-Mar-05 08:33 UTC
[CentOS] Disk read io very high, but no process perform io read
Hi,> We have experienced a very weird problem. The load of the server machine > is very high. We use "pidstat" and find that the disk read io is very > high.If disk read IO is very high, what does it read and what generates the reads? Simon> But the processes running on this server do not perform any disk read > operation. > We also noticed that when we execute "top" command, for most of processes, > the values in "SHR" column are zero. > Compared with other normal servers, we found that by executing "free -m", > the result shows that the buff/cache value in this server is lower than > the value of other normal servers. > We also found that there were lots of major page faults by executing "ps > -o majflt,minflt". > Swap is not enabled on this server. What could be the reason for this > issue? > > > The centos version:CentOS Linux release 7.3.1611 > kernel version:3.10.0-693.21.1.std7a.el7.0.x86_64 > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >
Joshua Kramer
2021-Mar-05 15:03 UTC
[CentOS] Disk read io very high, but no process perform io read
Install a program called iotop. iotop will show you, in real time, which processes are using the most i/o bandwidth. On Fri, Mar 5, 2021 at 2:54 AM yf chu <cyflhn at 163.com> wrote:> > We have experienced a very weird problem. The load of the server machine is very high. We use "pidstat" and find that the disk read io is very high. > But the processes running on this server do not perform any disk read operation. > We also noticed that when we execute "top" command, for most of processes, the values in "SHR" column are zero. > Compared with other normal servers, we found that by executing "free -m", the result shows that the buff/cache value in this server is lower than the value of other normal servers. > We also found that there were lots of major page faults by executing "ps -o majflt,minflt". > Swap is not enabled on this server. What could be the reason for this issue? > > > The centos version:CentOS Linux release 7.3.1611 > kernel version:3.10.0-693.21.1.std7a.el7.0.x86_64 > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos
Matthew Miller
2021-Mar-05 15:37 UTC
[CentOS] Disk read io very high, but no process perform io read
On Fri, Mar 05, 2021 at 03:54:14PM +0800, yf chu wrote:> We have experienced a very weird problem. The load of the server machine is very high. We use "pidstat" and find that the disk read io is very high.Is this system a VM? -- Matthew Miller <mattdm at fedoraproject.org> Fedora Project Leader