![]() ![]() High latency also affects the I/O performance, because there will be many timeouts. This includes the RTT.Ī very high avg RTT(ms) and retrans indicates there is high latency on the network. avg exe (ms) - This is the duration from the time that NFS client makes the RPC request to its kernel until the RPC request is completed.avg RTT (ms) - This is the duration from the time that the client's kernel sends the RPC request until the time it receives the reply.retrans - This is the number of retransmissions.The most important statistics to look out for are: Read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) Running nfsiostat without any argument should have an output similar to the following: 10.10.1.10:/data/share mounted on /samba/students: The nfsiostat command is used on the NFS client to check its performance when communicating with the NFS server. It uses the file /proc/self/mountstats as input and provides information about the input/output performance of NFS shares mounted on the system. The nfsiostat command works similarly to the iostat command, but is used for the NFS mount points on the server. You can also check dropped packet by running the following command on both the server and the client: nfsstat -o net If you are encountering excessive retransmissions, you may want to adjust data transfer buffer sizes, which are specified by the mount command options rsize and wsize. Open_noat open_dgrd close setattr fsinfo renewĠ 0% 0 0% 1648000 5% 27154 0% 8 0% 28320 0%įrom the above, the client is doing well as it has relatively few retransmission requests. On the NFS client, you run the following: nfsstat -c Also, it's very important to put the NFS server in the same subnet as the NFS client when designing the network. When the badcalls is greater than 0, than the underlying network needs to be checked, as there might be latency. The most important field to check is the badcalls, which represents the total number of calls rejected by the RPC layer. The output should be similar to the below: Server rpc stats: On the NFS server, run the following command: nfsstat -s The nfsstat command displays statistical information about the NFS and Remote Procedure Call (RPC) interfaces to the kernel. Understanding the output of the tools can help with optimizing NFS performance. The two most important tools I have used over the years to analyze the performance of NFS from both the server and client perspective are nfsstat and nsfiostat. The two tools are part of the nfs-utils package and its needs to be installed as such: yum install -y nfs-utils However, because NFS relies on the existing network infrastructure, any glitches on the network may affect the performance of the connection. It allows for fast, seamless sharing of files across a network. The network filesystem ( NFS) allows machines to mount a disk partition on a remote machine as if it were a local disk. How well do you know Linux? Take a quiz and get a badge.Linux system administration skills assessment.A guide to installing applications on Linux.Download RHEL 9 at no charge through the Red Hat Developer program.The AUD$10 per month for a static IP is well worth the investment compared to the stress and worry of being dependent on a third party providing a free service. access to an offsite backup site, but I will definitely avoid it where I have SLAs with my own customers. Once DNS-O-Matic services are restored, I'll still use it in non-critical situations e.g. I've moved from a very stressful situation not knowing when the broken DNS-O-Matic service would be restored, with no ongoing updates from OpenDNS support or Cisco, the parent company, to great relief for myself several small business customers I service. ![]() This incident has made me realise that I need to switch to a static IP, and I have. If you're doing anything serious, like serving customer websites, DNS-O-Matic represents a weak link in the chain. However, when there's a problem, being free, there's no well defined SLA.
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