This section presents guidelines for configuring the OneFS file system.
For assistance, contact your PowerScale account representative or PowerScale Technical Support.
Item | OneFS 9.8.0.0 | Description |
---|---|---|
Block size | 8 KB | The maximum block size limit. This limit cannot be changed. |
Cluster name length | 40 characters | The maximum length for the cluster name. |
Cluster size | 252 nodes | The maximum number of nodes that a cluster can have. |
Custom access pattern templates | 5 | The limit for custom file-system-tunable templates. This limit is in addition to the default templates of "random," "streaming," and "default." |
Directories per directory | 100,000 | The recommended limit for the number of directories in a directory. Exceeding this limit might negatively affect the cluster performance and client connections. Evaluate the workflow and workloads for your cluster to determine the value that works best for your environment. |
Directory depth | 509 | Maximum recommended depth of a directory tree is 509. |
FEC protection | +4n | The following FEC options are supported: +1n, +2n, +2d:1n, +3d:1n, +3d:1n1d, +3n, +4d:1n, +4d:2n, +4n. OneFS protection is defined at the node pool level. A cluster with multiple node pools can have multiple protection schemes simultaneously. The recommended protection level depends on the size of the node pool and node types. For information about disk pools, node pools, and tiers, see the white paper Storage Tiering with Dell EMC Isilon SmartPools. |
Mirrored protection | 8x (maximum) | Mirroring options from 2x to 8x are supported. The recommended value depends on the node pool size. |
File clones per file | 32,766 | The maximum number of references for a single block in a shadow store. When the limit for file clones per file is exceeded, a new shadow store is created. |
File name length | Up to 1024 unicode characters in namelength domains.
1024 bytes in regular directories. |
In namelength domains, OneFS can support upto 1024 unicode characters. In regular directories, OneFS supports a maximum filename length of 1024 bytes. Most Unicode character encodings, such as UTF-8, specify that a character can have multiple bytes. UTF-8 can have up to 4 bytes per characters. The characters in some languages, such as Japanese, are likely to have multiple bytes per character. OneFS supports UTF-8 by default. |
Standard file size | 4.398 TB (4 TiB) | The maximum size for a file for all PowerScale clusters. Files larger than 1 TB can negatively affect job engine performance. |
Expanded file size | 17.6 TB (16 TiB) | The maximum size for a file that can be supported with specific PowerScale hardware configurations. |
File system size | 181.44PB | The maximum capacity for the file system. The capacity size does not include overhead for the OneFS operating system, the file system, or data protection. |
Files per directory | 1,000,000 | The recommended limit for files per directory. Exceeding this limit might negatively affect the cluster performance and client connections. Evaluate the workflow and workloads for your cluster to determine the value that works best for your environment. To improve performance when managing large numbers of files in a single directory, use nodes that have solid-state drives (SSDs). |
Hard links per file | 1,000 | The default and maximum number of hard links per file. You can set the maximum number of hard links per file with the efs.ifm.max_links system control. Setting the number higher than the default value can slow snapshot operations and file deletions. For more information, see the EMC Isilon knowledge base article 447064, OneFS: Sysctl: efs.ifm.max_links. |
Inodes per cluster | Billions | OneFS dynamically allocates new inodes from free file system blocks. The maximum number of possible inodes depends on the number and density of nodes in the cluster, as expressed by the following formulas:
|
Logical Node Numbers (LNNs) | 252 | The limit for logical node numbers. |
Node pools per cluster | 20 | The recommended and maximum limits for node pools per cluster. The number of node pools that can be created is limited by the number of nodes in the cluster. |
Open files per node | 315,000 | The maximum number of open files per node depends on the maximum number of vnodes that are available on the node. The amount of available vnodes depends on how much RAM the node has. The maximum number of open files per node is 90% of the maximum number of vnodes on that node, as expressed in the following formula: kern.maxfiles = kern.maxvnodes * .9 The OneFS protocol daemons, such as the input-output daemon (lwio), might impose additional constraints on the number of files that a node can have open. The protocol daemons typically impose such constraints because the kernel places limits on per-process memory consumption. |
Path length | 4096 bytes |
The maximum length for a pathname. The length is the maximum length of a directory path that can be passed into a system call; it does not represent the absolute depth of nested directories. Shorter path and file names require fewer lookup operations. As a best practice, keep your path and file names as short as possible, especially in workflows that include many lookups. OneFS features like NDMP and SyncIQ may not work as expected on paths longer than the maximum limit. NOTE:For symbolic links, the path length of the target is restricted to 1024 bytes if the symlink source is in a restricted domain.
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Device IDs | 65,535 | Device IDs are unique identifiers for nodes. Device IDs are not reused when nodes are replaced. To reach the limit of Device IDs in a three-node cluster, you must replace nodes 65,532 times. |
User attribute keys | 16 | The limit of attribute keys that can be created within any file system object. The user attribute term refers to custom file system metadata that the FreeBSD extattr API creates. These extended attribute data types can be acted on by SmartPools, for example, by choosing the File Attribute file pool policy filter. Extended attributes exist as "name=value" pairs within a file system object. |
User attribute key size | 24 bytes | The limit size for the user attribute key. |
User attribute value size | 128 bytes | The limit size for the user attribute value. |
User attribute total size | 1 KB | The limit for the size of the custom metadata that is associated with the file system object. |