Using EVMS with NSS allows you to take advantage of the full range of capabilities of NSS and the NSS management tools, including the Storage plug-in to Novell iManager 2.5, NSS Management Utility (NSSMU), and NSS utilities and commands. NSS tools require EVMS for management functions related to devices, software RAIDS, partitions, and pools.
For information about limitations for NSS on devices managed by non-EVMS volume managers, see Does NSS Work with Non-EVMS Volume Managers?.
NSS file systems work on devices that are managed by any volume manager. However, the following NSS capabilities are unavailable or have limited availability for devices managed by a non-EVMS volume manager:
NSS Management Tools: The following NSS management tools are affected:
The Storage plug-in for Novell iManager 2.5 requires that EVMS be used as the volume manager of any devices where you want to create and manage NSS file systems. The tool does not work with devices managed by non-EVMS volume managers.
The NSS tools, utilities, or commands that are used to manage devices, create and manage software RAID devices, create and manage partitions, and create pools require EVMS. However, with a non-EVMS volume manager, you can perform these tasks with Linux tools and utilities or with third-party tools.
NSSMU requires EVMS to manage partitions, to manage devices, to create and manage software RAIDs, and to create pools. Without EVMS, you can use some management functions for NSS pools, but you cannot create them.
You can use NSSMU to create and manage both non-encrypted and encrypted volumes for the existing pools you create from the Linux command line.
NSS Software RAIDS: NSS requires EVMS to create and manage software RAID devices. If you want to create software RAIDs, use the capability in whatever non-EVMS volume manager you use.
Cross-Platform Compatibility: Pools created on devices managed by non-EVMS volume managers cannot be moved to a NetWare® server.
Clusters: Novell Cluster Services™ (NCS) for Linux requires EVMS for clustering. Pools created on devices managed by non-EVMS volume managers cannot be used in NCS clusters. Third-party clustering systems that integrate with third-party cluster volume managers should be able to work with NSS volumes.
To use NSS with a non-EVMS volume manager, create partitions and pools with the Linux mkfs command, then use NSSMU and NSS volume management commands to manage the volumes. For information, see Using NSS on Devices Managed by Non-EVMS Volume Managers
in the Novell Storage Services File System Administration Guide for OES.
The Linux 2.6 and later kernel prevents multiple volume managers from managing the same device, so you should decide which volume manager to use for devices based on how you plan to use the space on those devices and the tools you want to use to manage them.
Linux requires traditional Linux file systems for system partitions such as the boot (/boot), swap, and root (/) partitions. NSS volumes on Linux are configured as data volumes after the install; they cannot be configured at install time.
At install time, OES Linux uses LVM (Linux Volume Management) as the default volume manager for the system device and any other devices that you configure for traditional Linux volumes. When you later create NSS volumes, the NSS tools recognize only those devices that are managed by EVMS or that are unconfigured; it does not find devices managed by LVM. If you have a single device or if you have multiple devices and choose to mix traditional Linux file systems and NSS file systems on the same device, volume manager issues affect how you can use or manage storage after the install.
Before you install OES Linux, you should consider deployment solutions that reserve a device for NSS or configure devices to use EVMS at install time. This allows you to take advantage of the full capabilities of NSS management tools for NSS file systems. For information, see Storage Deployment Scenarios for NSS.
If you decide to use the LVM defaults at install time, you can still use unallocated free space on the devices for NSS file systems after the install. For information, see Can I Use NSS After the Install If Existing Devices Do Not Use EVMS?.
During an upgrade, you can modify the suggested Partitioning settings to use EVMS instead of LVM for the system device. This action deletes the existing LVM partitions and partition tables and creates new partitions and partition tables.
WARNING:Re-partitioning a device during the install destroys all data on the device. To prevent data loss, it is best to use the modified install option only on a new device.
If the system device also contains data volumes, take one or more of the following precautionary measures before you upgrade:
Move all data volumes off the system device to another device.
If you cannot move the volumes, make a backup copy of the data volumes, so you can restore the data volumes later from a backup copy.
If you do not configure devices at install time to use EVMS, it is still possible to use NSS file systems on the server. Use any of the following approaches:
Add a new device. Add an unconfigured device to use for NSS volumes. Use the Storage plug-in to iManager or NSSMU to create at least one NSS volume on the device before you create any traditional Linux file systems on it. This ensures that EVMS automatically controls the device.
Reconfigure the device to use EVMS as the volume manager: Set up the device to use EVMS without re-installing OES Linux. You can then use the Storage plug-in to iManager or NSSMU to create NSS pools and volumes in the unallocated free space on the device.
For information, see Making Devices Available to EVMS
in the Novell Storage Services File System Administration Guide for OES.
Use NSS with the non-EVMS volume manager. Use the Linux mkfs command to create NSS partitions and pools with the unallocated free space. You have limited capability to manage NSS volumes, as described in Does NSS Work with Non-EVMS Volume Managers?.