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Configuring NFS servers 5–5

5.1.3.2 NFS performance scaling example

Figure 5-2 illustrates how performance is affected when the number of NFS servers and client systems is

increased in a system configured as in Figure 5-1.

Figure 5-2 NFS performance scaling

5.1.4 NFS access — file and file system considerations

Because NFS Version 3 client systems issue 32KB transfer size requests, the layout of the Lustre stripe size

can impact performance. The stripe size is set when the Lustre file system is created; however, you can

override this by setting the stripe size for individual files using the lfs setstripe command.

For optimum NFS performance, the stripe size must be a multiple of 32KB. If the default stripe size for the

file system (4MB) is chosen, or if the rules described in Chapter 6 for individual files are applied, the stripe

size will always be a multiple of 32KB.

5.1.5 Optimizing NFS client system performance

To optimize NFS performance, consider the following recommendations for NFS client systems:

• Increase the NFS file system block size by adding the following parameters when mounting the NFS

volume:

wsize=32768

rsize=32768

proto=tcp

nfsvers=3

These parameters can be specified when the mount command is entered, or by placing them in the

/etc/fstab file. For more information, see the mount(8) and nfs(5) manpages.

• On NFS Linux client systems, kernels at Version 2.6 or later have shown better performance (by as

much as 30%) than kernels at Version 2.4.

• If file or record locking is going to be used, ensure that the NFS lock daemon is enabled on both the

NFS client system and the NFS server.

NFS performance scaling

HP SFS Version 2.2-0

50000

100000

150000

200000

250000

1234

Number of NFS servers and NFS clients

Aggregate throughput in KB/se

Initial write

Rewrite

Read

Re-Read

Default stripe size; Default stripe count

nfs_readahead=0; 8GB files

1 2 ... 76 77 78 79 80 81 82 83 84 85 86 ... 133 134

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Red Hat GLOBAL FILE SYSTEM 4.7 Guida Utente Pagina 81