HP StorageWorks Scalable File Share - Manual (Page 352)

HP SFS specifications E–2
E.1 Supported number of Object Storage Servers
HP SFS supports a maximum of 64 Object Storage Servers. This means that the maximum number of servers
in a system is 66, including 64 Object Storage Servers, one administration server, and one MDS server. In
this maximum configuration, the administration and MDS servers must not run OST services.
E.2 Supported number of OST services
The maximum number of OST services supported in a file system is 256.
E.3 Supported number of file systems
The maximum number of file systems that is supported in an HP SFS system is 31. Note that when you run
the
create filesystem
command to create a file system, the command does not check whether the
maximum supported number of file systems has already been created.
E.4 File and file system limits
• The largest MDS LUN that can be created on a storage array is 2TB. This means that when the
suggested rule of allowing 4K per file on an MDS LUN is applied, the largest possible number of files
in one file system is 512M, (that is, just over 500 million). This number can be made lower
depending on the number of OST services in the file system, and on the file stripe count. For more
information, refer to Chapter 5 of the HP StorageWorks Scalable File Share System Installation and
Upgrade Guide, specifically the MDS LUN sizing guide section.
• Lustre has no built-in file system limits. However, the largest number of supported Object Storage
Servers in an HP SFS system is 64. Based on this, the largest possible file system is as follows:
• For systems using EVA4000 storage:
64 (Object Storage Servers) x 2 (Controllers) x 2TB = 256TB
• For systems using SFS20 storage:
64 (Object Storage Servers) x 4 (SFS20 array limit) x 2TB (OST limit on SFS20) = 512TB
NOTE: Where 500GB disks are used, an SFS20 array can provide a total of 4TB of storage.
However, this must be configured as two LUNs of 2TB each, and as the maximum number of
OST services supported in a file system is 256, the maximum file system size is still 512TB, even
where 500GB disks are used.
• The largest file that can be created on a Lustre file system on 32–bit client nodes is 16TB; this limit is
imposed by the
vm
subsystem and the page size. However, HP recommends that 32–bit client nodes
do not create or access files larger than 8TB. For all other architectures, the file size is limited by the
size of the file system. Note that if you create a file that is not striped across all OST services in the file
system, the effective file size limit is reduced proportionately.
• The maximum stripe count on any one file is 160, which limits the maximum file size accordingly.
E.5 Maximum file system default stripe size is 1024MB
The maximum stripe size that you can specify as the default for files in a file system is 1024MB. (The file
system default stripe size is set when the file system is created; see Section 5.1.4 and Section 5.2.2 for more
information.)