Red Hat GLOBAL FILE SYSTEM 4.7 Guide de l'utilisateur télécharger pdf (Page 88)

User interaction with Lustre file systems6–4

6.1.3 Setting a default stripe size on a directory

If you want to create many files with the same stripe attributes and you want those files to have a stripe

configuration that is not the default stripe configuration of the file system, you can create the files individually

as described earlier in this chapter. Alternatively, you can set the stripe configuration on a subdirectory and

then create all of the files in that subdirectory. All of the files created in the subdirectory will inherit the stripe

attributes of the subdirectory in preference to those of the file system.

For example, the following code creates10 files in one subdirectory, with the stripe configuration of the files

defined by the stripe setting of the directory. Each file has a stripe size of 8MB, and has two stripes, with

the first stripe on each file being on the first OST service:

# mkdir ./stripe_example

# lfs setstripe ./stripe_example 8388608 0 2

# for i in ‘seq 1 10‘ do ; echo $i > ./stripe_example/file${i} ; done

When a subdirectory is created, it inherits the default stripe pattern of the containing directory.

Note that the stripe size attribute on the directory must be at least the size of the page size on the client

node. Where the stripe size is larger than this minimum value, it must be an exact multiple of the page size.

6.2 Dealing with ENOSPC or EIO errors

Your application may encounter the ENOSPC error code (or alternatively the EIO error code). In traditional,

nonparallel file systems, such errors usually mean that all of the file system storage is occupied with file data.

With a parallel file system such as Lustre, there are other possible explanations for the error. The following

are the most likely reasons for the error:

• The number of inodes available for the file system or for the OST services in the file system may be

used up.

• One or more of the OST services in the file system may be full.

• The file system may be completely full.

Section 6.2.1 through Section 6.2.3 describe how to determine if the error is caused by one of the first two

reasons, and if so, how to deal with the problem.

If the file system is completely full, you will not be able to create new files on the file system until one or both

of the following actions are taken:

• Existing files are deleted

• More OST services are added to the file system

Instructions for adding OST services to a file system are provided in the Adding OST services to a file

system section in Chapter 5 of the HP StorageWorks Scalable File Share System User Guide.

If the default email alerts are being used on the HP SFS system, an out-of-space alert will be delivered to a

system administrator when the file system service usage reaches a certain level—usually before an

application error is encountered.

The Managing space on OST services in Chapter 5 of the HP StorageWorks Scalable File Share System

User Guide describes how to monitor the system for full OST services and how to manage out-of-space alerts.

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Red Hat GLOBAL FILE SYSTEM 4.7 Guide de l'utilisateur Page 88