How to use Storagepools
From SEPsesam
Contents |
Introduction
A Media Pool is referenced to one point on a storage system. In consequence in case of growing memory requirements the storage system just reaches its capacity and cannot be extended anymore. It's not possible to add additional space of further storage devices to the same Media Pool with the former Media Pool configuration dialog. From SEP sesam version 3.4 upward therefore an additional option is introduced - the Storage Pool.
Description
Storage Pools expands Media Pools to an additonal level. This means that Media Pools can consists of 1-N Storage Pools. This ensures a dynamical extension of the Media Pool. If necessary a further Storage Pool is just assigned to the Media Pool.
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Please pay attention that normally configured Media Pools can not be extended with Storage Pools at the moment. |
On the left hand side of figure above the classical usage of Media Pools is shown. The Media Pool is referenced to /sesamdisk on the filesystem. Beneath this point Sesam creates the virtual media. In contrast the right hand side illustrates a Media Pool by using Storage Pools SP01, SP02 and SP03. This example shows a Media Pool consisting of 3 Storage Pools which references to a disk storage on filesystem mounted via NFS and/or external storage media. E.g. if the NFS share of SP02 is mounted to /sesam_nfs/sp02 in local filesystem of the SEP sesam server you can register media to the Storage Pool SP02 and the corresponding subdirectories of every media will be created under this location.
Configuration
Example 1 will show the configuration of a Media Pool with using Storage Pools with static access. That means the Storage Pool locations are existing permanently in the locale filesystem.
Data for example 1:
- Media Pool definition
- Name of the Media Pool = SPstatic
- Media Pool size = 1 GB
- size of a single media = 100 MB
- Storage Pool definition
- Name of Storage Pool 1 = SPstat1
- Storage Pool 1 size = 300 MB
- Storage Pool 1 location = /srv/SPstatic/SPstat1
- Name of Storage Pool 2 = SPstat2
- Storage Pool 2 size = 600 MB
- Storage Pool 2 location = /srv/SPstatic/SPstat2
Example 2 will show the configuration of a Media Pool with using Storage Pools by using the advanced feature Dynamic Access. This feature provide a possibility to mount a Storage Pool just in time of using. This feature only works if the operating system this functionality supports. To demonstrate how it work we use loop devices in this example.
To reprocude this example:
- Create to files with 500 MB size each and format them with ext3
- dd if=/dev/zero of=/srv/storage/loopdev01 bs=500M count=1
- mkfs.ext3 loopdev01
- dd if=/dev/zero of=/srv/storage/loopdev02 bs=500M count=1
- mkfs.ext3 loopdev02
Data for example 2:
- Media Pool definition
- Name of the Media Pool = SPtest
- Media Pool size = 1 GB
- size of a single media = 100 MB
- Storage Pool definition
- Name of Storage Pool 1 = SP01
- Storage Pool 1 size = 500 MB
- Storage Pool 1 location = /srv/storage/SP01
- Name of Storage Pool 2 = SP02
- Storage Pool 2 size = 500 MB
- Storage Pool 2 location = /srv/storage/SP02
Create a Media Pool
The creation of a Media Pool is in both examples the same way. If you create a new Media Pool the Storage Pool option will not be displayed.
Modify the Media Pool
Edit the Media Pool configration to switch on the Storage Pool option.
- Activate the option use Storage Pools. A additional dialog page and a additional button appear.
- Press the button Storage Pools to create new or edit existing Storage Pools.
Example 1 with static Storage Pools
Create Storage Pools
- Create SPstat1 by clicking button New, after the input finish by button Apply
- Create SPstat2 by clicking button Copy, change the values as requested, then button Apply
- After creation of all necessary Storage Pools close the Dialog by select button OK
Assign the Storage Pools to the appropriate Media Pool
Example 2 with dynamic Storage Pools
Creation Media Pool and switching on Storage Pool option is descibed above. After pressing button Storage Pools you can create new, modify and/or delete existing Storage Pools.
Create Storage Pools
- Name Name of storage pool.
- Path Shows the location on the file system where the virtual media of that pool are created. NFS shares or external volumes which are dynamically mounted on the system can be used as well.
- Capacity The maximum size in MB which may be allocated on the storage device by that pool.
- Description optional
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That is all we have to configure to operate with a static Storage Pool and is equivalent to example 1. The dynamic allocation while operating is a special and advanced feature. However it's only possible if both the operation system and the plugged devices support script based mounting and unmounting. The configuration dialog of Storage Pools in figure above illustrates the interaction. |
- Command for Loading (optional) Command which is used by the operating system to mount a dynamic storage device. A external script can be used as well. This script gets the device path as first parameter.
- Command for Unloading (optional) Command which is used by the operating system to unmount a dynamic storage device. A external script can be used as well. This script gets the device path as first parameter.
- Device Path Specifies the device path to the storage device.
The example shows a loop mounted volume which is dynamically mounted and unmounted in the system depending on how SEP sesam handles the Media Pool above. This means by every action a medium of that Storage Pool is used the device file is mounted on the file system and after using will be unmounted.
Assign the Storage Pools to the appropriate Media Pool
You can select the desired Storage Pools from the pick list and move them to the picked list. With the priority value you can control in what order the Storage Pools will be used on backup.
Register media to the Media Pool
For every Storage Pool in the Media Pool you have to register the medias in a separate step by Archive Adjustment. Select the Loader view in the SEP sesam GUI (Components/ Loaders in the object panel on the left) and start the Achive Adjustment by selecting the button with the name Archive Adjustment.
The description relates to the values of example 1.
- Select and enter the following values for the fields:
- Media Pool = SPstatic
- Storage Pool = SPstat1 --> is the first Storage Pool
- First slot leave 0 (zero). The slot counting begins always at zero, the automatic numbers for medias begins at 1 (e.g. SPstatic00001).
- Last slot = 2 - because 3 new media should be created. If no media exists for the Media Pool the default value is -1. calculate from last slot (2) of a existing media from Storage Pool 1 (SPstat1)
Initiate the archive adjustment by pressing the Start button and wait until the Message of success ('Archive adjusting completed successfully'= displayed in the Current messages window. Then start the Archive Adjustment for the next Storage Pool.
- Call the function Archive Adjustment again for creating new media in Storage Pool SPstat2. Select...
- Media Pool = SPstatic
- Storage Pool = SPstat2 --> is the next Storage Pool
- First slot leave 0 (zero)
- Last slot = 8 (calculate from last slot (2) of a existing media from Storage Pool 1 (SPstat1) added with 6 new media in Storage Pool 2 (SPstat2) results in 8)
