The following measures may be required on the NFS clients on which bs2fs file systems are mounted:
Disable the attribute cache
As the size of a bs2fs file can change when the first open() takes place, the file attributes on the NHS client should not be stored in the attribute cache. On NFS clients the mount option noac, for example, is available to prevent this.Permit increased response times
Because of the unexpectedly long response times, especially with the NFS function ACCESS, the timeout values specified on the NFS client must be sufficiently high. On NFS clients the mount option timeo=n, for example, is provided for this purpose. Depending on the size of the bs2fs files, ten times the default value or even more must be set here.
If relatively large bs2fs files are to be processed, it may be necessary to perform a socalled "hard mount" (as a rule by omitting the mount option soft). As a result of this file accesses are always repeated after timeouts.Disable the READDIRPLUS function
Using the NFS function READDIRPLUS instead of READDIR is designed to reduce the number of network I/Os and consequently to enhance the performance. However, a loss of performance may under some circumstances be recognized on some NFS clients. These offer, for example, a mount option nordirplus in order to disable the use of READDIRPLUS.Disable input/output buffering
Some NFS clients use local buffering of the input/output data to reduce the number of network I/Os. This can, however, lead to possible input/output errors in bs2fs files being concealed, as a result of which the application on the NFS client incorrectly assumes that an input/output was successful. Input/output buffering on the NFS client should therefore be disabled. On NFS clients the mount option forcedirectio, for example, is available for this purpose.