David, ----- "Daire Byrne" <Daire.Byrne@xxxxxxxxxxxxxx> wrote: > I have been testing a "live" Linux USB stick distro that we intend to > give to employees who are working from home (VPN). They put the USB stick > in their Windows or Mac PCs and it boots up an environment identical to the > Linux setup in the office. All our NFS (automount) maps are accessible and > fscache stores data on the USB stick. In tests this has been working great and > is a very useful way of teleworking. After testing this over the last couple of weeks I am quite happy with the results - NFS caching is great for VPNs and teleworking! There are a few things that still could be better though. Does it make any sense to have a concept of "lazy" netfs lookups whereby if I know that the netfs filesystem won't be changed I can go straight to the cache and not have to go to the network at all? Maybe not quite disconnected in the sense that perhaps you can relookup the network every 10 mins or so. This would be great for high latency networks and small file access. Also would it be possible to cache the contents of dir in a similar fashion? So for example if I mount my home dir over a slow link and have some subdir in my PATHs, applications will only need to go to the network the first time to check the existence of a file in a dir (e.g. PATH etc.). With something like Lustre perhaps this all becomes far more efficient due to the DLM - you only go to the network when you are notified of a PAGE change? Or would you need to keep locks on all cached files for that? Another application for NFS caching I was thinking about was for storing VM images. It is necessary to keep VM images on shared storage for easy migration but you want to minimise the NFS traffic and utilise local storage if possible. Would caching the read parts of the image on disk should help? Like before if I know that the VM instance is based on a read-only QCOW2 image would it help to force the NFS cache to never revalidate what is on the net and go straight to the cache? Obviously writes always have to go to the net. Apologies if these questions are a bit silly - I'm not much of a programmer! Daire -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cachefs
