HP StorageWorks Scalable File Share - Manual (Page 102)

Creating and modifying file systems 5–18
Mount options
Underlying the OST and MDS services on the Lustre file systems, there are
ldiskfs
file systems. When an
OST or MDS service starts, it mounts the underlying
ldiskfs
file system so that it can access the data. You
can specify mount options on the file system services to determine what happens when the file systems are
mounted.
• When creating a file system, accept the default options provided by the
create filesystem
command for OST services.
• You can optionally set the
acl
and
user_xattrs
options for MDS services:
• The
acl
option must be enabled if Access Control Lists (ACLs) are to be used when the file
system is mounted on client nodes.
• The
user_xattrs
option must be enabled if extended attributes are to be used when the file
system is mounted.
HP recommends that you enable the ACL functionality on your HP SFS file systems, unless your system is
running in Portals compatibility mode.
CAUTION: If your system is running in Portals compatibility mode, do not enable the
acl
option or the
user_xattrs
option on a file system. Client nodes will not be able to successfully mount a file system that
has these options enabled while the system is running in Portals compatibility mode.
Stripe count
The stripe count specifies the number of OST services that files are striped over. The suggested stripe count
is one.
NOTE: In earlier versions of the HP SFS software, a stripe count of 0 (zero) resulted in files being striped
over all OST services in the file system. Since HP SFS Version 2.1, this is no longer the case; a stripe count
of 0 now results in files being striped over a single OST service.
The stripe count cannot be larger than the number of OST services assigned to the file system. HP
recommends a stripe count of one for most applications; this stripe count has been shown to provide
maximum aggregate file system bandwidth (see Appendix B for performance figures).
Note that you can apply different custom default stripes to directory trees in the file system after file system
creation (refer to the HP StorageWorks Scalable File Share Client Installation and User Guide for more
information). You can also use the
modify filesystem
command to add OST services to an existing file
system (see Section 5.6 of this guide).
Interconnects
You will be asked to specify the interconnects that can be used for file system I/O operations. The accessible
interconnects will be listed and you can choose to use some or all of them.
Quota options
Quotas on file systems allow you to specify limits on two aspects of disk storage:
• The number of inodes a user or a group of users may possess.
• The number of disk blocks that may be allocated to a user or a group of users.
Quotas ensure that users do not consume more than their allocated disk consumption limit. Quotas are
handled on a per-user/group, per-filesystem basis. If a user is expected to create files in more than one file
system, quotas must be set for each of the file systems.