Difference between revisions of "Greyhole"

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= Greyhole =
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[[Category:apps]]
 +
== What is Greyhole ==
  
A new feature in Amahi is [[Storage pooling]] using [http://greyhole.pommepause.com/ Greyhole].
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[http://www.greyhole.net/ Greyhole] is Amahi's [[Storage pooling]] technology of choice. Storage Pooling combines the space of multiple disk drives and makes them look as if they were all part of a single pool of disk space. Greyhole was designed independently of Amahi, however, with feedback and great work, the Greyhole team made it suitable for integration with Amahi.
  
This feature is installed by default, but requires a few simple steps to begin utilizing the features.
+
Specifically, Greyhole:
 +
* Combines the space from multiple drives into a single volume
 +
* Distributes files across all drives in the pool
 +
* Creates multiple copies of files in admin-specified shares
 +
<br />
 +
Recommend you consult [https://github.com/gboudreau/Greyhole/wiki/WhatNotToPutInGreyholeShares what not to put in Greyhole shares] as a precaution when determining which shares to select.
  
You can add additional drives to your hda and prepare them for use in Greyhole by following [[Adding a second hard drive to your HDA|this tutorial]].
+
You can add additional drives to your HDA and prepare them for use in Greyhole by following [[Adding_a_second_hard_drive_to_your_HDA|adding a second hard drive to your HDA]] guidance or use the Amahi [https://www.amahi.org/apps/disk-wizard Disk Wizard] (Amahi 8 or greater).
  
To add a drive to your Greyhole storage pool. First open your dashboard and navigate to the Shares tab. Then click on the Storage Pool sub-category. You will see a page similar to the one below.
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{{Warning|
 +
<div style<nowiki>=</nowiki>"color:darkred">You should <u>'''NEVER'''</u> change or delete files in the shared directories (''/var/hda/files/*'' by default) directly on the HDA, using the terminal, or the Gnome file browser, for the shares for which you checked the ''Uses pool'' option in the Amahi dashboard. If you want to work with files on Greyhole shares on the HDA, you should [[Mount Shares Locally]].<br/>
 +
<br/>
 +
You should be safe reading existing files directly, or adding new files directly, as long as don't care that your new files will only be moved into the storage pool during the next check, which runs automatically at midnight (or manually using ''greyhole --fsck''). Until then, your new files will be stored in your shared directories (normally ''/var/hda/files/share_name/'').
  
== For Storage Pool (Partitions) ==
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Also, touching anything inside the '''gh''' directories that Greyhole creates at the root of your partitions is a recipe for disaster.  [[Greyhole not on root|We strongly discourage you from using the root partition in a drive pool]].</div><br/>}}
  
[[File:Storage_Pool_1.png|600px|thumb|left]]
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'''NOTE:'''  All commands are executed as root user (Fedora) or preceded with sudo (Ubuntu).
 +
 
 +
== Amahi 7 or greater ==
 +
Amahi application [https://www.amahi.org/apps/greyhole-ui Greyhole UI] provides this capability.  Refer to the [[Greyhole_UI_App_Transition_Guide|Greyhole UI Application Transition guide]] for details on installation and configuration.
 +
 
 +
'''NOTE:''' If you would still like to setup your Greyhole pool manually, please see [[Amahi_Create_Manual_Greyhole_Setup|Manual Greyhole Setup]].
 +
 
 +
== Amahi 6 ==
 +
 
 +
You need to go in the Settings tab, and select [[Advanced_Settings|Enable Advanced Settings]].  Without Advanced Settings enabled, you won't see the following page and options.
 +
 
 +
<b><u>Storage Pool</u></b><br />
 +
 
 +
[[File:Storage_Pool_1.png|600px]]
  
 
Select the drives you want available for your storage pool.
 
Select the drives you want available for your storage pool.
  
== Greyhole options ==
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<b><u>Share Options</u></b><br />
  
 
The next step is to select the share you want to replicate across the pool.
 
The next step is to select the share you want to replicate across the pool.
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From the Shares tab, select the Shares sub-catagory. We chose the Pictures share for this tutorial.
 
From the Shares tab, select the Shares sub-catagory. We chose the Pictures share for this tutorial.
  
[[File:Greyhole_Options_1.png|600px|thumb|left]]
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[[File:Greyhole_Options_1.png|600px]]
  
 
Check the option for "Uses pool" and choose the number of drives to replicate this share. In this instance we have chosen to use all drives available to the greyhole pool.
 
Check the option for "Uses pool" and choose the number of drives to replicate this share. In this instance we have chosen to use all drives available to the greyhole pool.
  
Note: Greyhole is not a backup solution. If a file is removed, all copies are removed.
+
'''NOTE:''' Greyhole is not a backup solution. If a file is removed, all copies are removed.
 +
 
 +
== Advanced Options ==
 +
 
 +
You can further configure Greyhole by manually editing '''/var/hda/platform/html/config/greyhole.yml'''. 
 +
 
 +
:'''NOTE:''' Options duplicated in ''/etc/greyhole.conf will be overridden by grehole.yml.
 +
 
 +
To see what options are available, and what they do, refer to the [https://github.com/gboudreau/Greyhole/blob/master/greyhole.example.conf sample greyhole.conf] provided with Greyhole.
 +
 
 +
greyhole.yml is in in [http://en.wikipedia.org/wiki/YAML YAML] format. Most of it should be easy enough to modify. The only exception would be the sticky_files (and optional sticky_into) options.<br/>
 +
 
 +
Here's an example of how those should appear:
 +
 
 +
To specify the following to Greyhole in greyhole.conf:
 +
 
 +
<pre>sticky_files <nowiki>=</nowiki> Music/
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sticky_files <nowiki>=</nowiki> Videos/Movies/
 +
    stick_into <nowiki>=</nowiki> /mnt/hdd1/gh
 +
    stick_into <nowiki>=</nowiki> /mnt/hdd5/gh
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sticky_files <nowiki>=</nowiki> Backups/CrashPlan/
 +
    stick_into <nowiki>=</nowiki> /mnt/hdd0/gh</pre>
 +
 
 +
one should specify this in the greyhole.yml file, where '''precise indentation matters''':
 +
 
 +
<pre>sticky_files:
 +
- - Music/
 +
- - Videos/Movies/
 +
  - - /mnt/hdd1/gh
 +
    - /mnt/hdd5/gh
 +
- - Backups/CrashPlan/
 +
  - - /mnt/hdd0/gh</pre>
 +
 
 +
Once finished, it's important that you check to see the file is properly formatted.  To do so, do the following:
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cd /var/hda/platform/html/config
 +
echo 'require "yaml"; YAML::load(File.open("greyhole.yml"))' | irb
 +
 
 +
If you do not see any errors, then your ready for the next step.  Otherwise, ensure you correct the errors before proceeding.
 +
 
 +
For the changes to be effective, you will need to force Amahi to:
 +
 
 +
:<u>Ubuntu</u><br />
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:Regenerate the greyhole.conf file by editing a share, clicking it's path, and just clicking the Save button without actually changing the path.
 +
 
 +
:<u>Fedora</u><br />
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:Restart the Dashboard with any one of these alternatives as [[Open_terminal|root user]]:
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 +
:* touch /var/hda/platform/html/tmp/restart.txt
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:* systemctl restart httpd.service
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:* reboot
 +
 
 +
:Then regenerate the greyhole set up by changing any setting in Shares or in Drive pooling.
 +
<!--== Convert Greyhole from SQLite to MySQL ==
 +
Greyhole is already using MySQL in Amahi 6.0
 +
 
 +
Greyhole was previously using SQLite as the default database for queueing up tasks on Amahi. This was unique to Amahi as Greyhole was originally designed to use MySQL for this task.
 +
 
 +
There are some major performance benefits to using MySQL over SQLite when writing large amounts of files. Switching can be especially useful when moving data to Greyhole shares for the first time. For now there is a script you can run if you want to switch over. This script has been tested to be safe while Greyhole is working but should be used with discretion.
 +
 
 +
''To Convert to MySQL, run as root:''
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 +
/usr/share/greyhole/db_migration-sqlite2mysql.sh
  
== Copying you data into Greyhole shares the first time ==
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To see what DB engine is Greyhole using, do this:
  
When you start using Greyhole, you might want to copy or move all your exiting files into your new shares that use the storage pool.
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grep db_engine /etc/greyhole.conf
 +
-->
  
Note: This is not necessary if your files are already in Amahi shares. If they are there, and you enable the ''Uses pool'' option in the Amahi dashboard, the files will start getting moved around into the drives in your storage pool during the night (starting at midnight), when the nightly storage pool check starts.<br/>
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== Tips and Best Practices ==
The instructions below are for users who have more data to copy into the Greyhole shares than their currently free space in the /var/hda/files/ folder.
 
  
Once way to do that is to mount the shares that use the Greyhole storage pool, either on the HDA itself, or on a client computer on your local network, and copy your data from their existing location into the mounted shares.
+
Refer to [[Greyhole_Tips|Greyhole Tips]] for additional guidance.
This can be time consuming, but it is the safest way to use Greyhole.
 
  
Note that you should '''never''' write or modify files directly in the shared directories on the HDA itself, i.e. /var/hda/files/share_name by default. This applies to all shares for which you checked the ''Uses pool'' option in the Amahi dashboard.
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== Testing and Reliability ==
  
Another way to move your files from their current location into the storage pool is to share their current location using an Amahi share that ''Uses pool'', then let Greyhole nightly check move the files from there into the pool.
+
Check out the [[Greyhole grinder]] to help make Greyhole rock solid.
  
Here's a more detailed walkthrough for this method:
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== References ==
 +
* Good [http://revxatlarge.blogspot.com/2011/04/restoring-deleted-files-in-greyhole-and.html article] on Greyhole with terms explained.
  
# Setup the Greyhole Storage Pool in the Amahi dashboard, Shares > Storage Pool page.
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* [https://github.com/gboudreau/Greyhole/wiki Greyhole Wiki]:  Provides additional guidance and information.
# Go in the Shares > Shares page. In there, make sure you have an existing share for each share you have data for. Create new ones if you need, remove the ones you don't need.
 
# Edit the ''path'' of each of those shares, and enter the current location of your existing data. For example, the Movies share could have a path = ''/media/External Drive/Movies''
 
# Enable the ''Uses pool'' option for each of your shares, and select the number of extra copies you'd like, if any.
 
# Now, you either need to wait for Greyhole'S nightly check to start, or you can start it manually from a terminal, as root, using this command: greyhole --fsck
 
# Monitor /var/log/greyhole.log to see what's the ''fsck'' operation is done.
 
# Once ''fsck'' is done, your data has now been moved into the Greyhole storage pool (in the drives you selected in Shares > Storage Pool). All that should be left in the previous location of your data (''/media/External Drive/Movies'' from the previous example) should be symbolic links pointing to the new file copies.
 
# Move all those symlinks from there into the correct folders in /var/hda/files/share_name
 
# Back in the Amahi dashboard, edit the path of the shares once again, and put back ''/var/hda/files/share_name'' (i.e. the folders where you moved the symbolic links).
 
  
You're done. All your existing data is now stored in the various drives included in your storage pool, and are accessible via the Samba shares you have defined in the Amahi dashboard.
+
* [https://github.com/gboudreau/Greyhole/wiki/MigrateFromWHS Windows Home Server (WHS) Drive Extender Migration Guide]:  Move from WHS to Amahi and Greyhole.
 +
<br />

Latest revision as of 01:30, 17 January 2017

What is Greyhole

Greyhole is Amahi's Storage pooling technology of choice. Storage Pooling combines the space of multiple disk drives and makes them look as if they were all part of a single pool of disk space. Greyhole was designed independently of Amahi, however, with feedback and great work, the Greyhole team made it suitable for integration with Amahi.

Specifically, Greyhole:

  • Combines the space from multiple drives into a single volume
  • Distributes files across all drives in the pool
  • Creates multiple copies of files in admin-specified shares


Recommend you consult what not to put in Greyhole shares as a precaution when determining which shares to select.

You can add additional drives to your HDA and prepare them for use in Greyhole by following adding a second hard drive to your HDA guidance or use the Amahi Disk Wizard (Amahi 8 or greater).

Warning!
You should NEVER change or delete files in the shared directories (/var/hda/files/* by default) directly on the HDA, using the terminal, or the Gnome file browser, for the shares for which you checked the Uses pool option in the Amahi dashboard. If you want to work with files on Greyhole shares on the HDA, you should Mount Shares Locally.


You should be safe reading existing files directly, or adding new files directly, as long as don't care that your new files will only be moved into the storage pool during the next check, which runs automatically at midnight (or manually using greyhole --fsck). Until then, your new files will be stored in your shared directories (normally /var/hda/files/share_name/).

Also, touching anything inside the gh directories that Greyhole creates at the root of your partitions is a recipe for disaster. We strongly discourage you from using the root partition in a drive pool.


NOTE: All commands are executed as root user (Fedora) or preceded with sudo (Ubuntu).

Amahi 7 or greater

Amahi application Greyhole UI provides this capability. Refer to the Greyhole UI Application Transition guide for details on installation and configuration.

NOTE: If you would still like to setup your Greyhole pool manually, please see Manual Greyhole Setup.

Amahi 6

You need to go in the Settings tab, and select Enable Advanced Settings. Without Advanced Settings enabled, you won't see the following page and options.

Storage Pool

Storage Pool 1.png

Select the drives you want available for your storage pool.

Share Options

The next step is to select the share you want to replicate across the pool.

From the Shares tab, select the Shares sub-catagory. We chose the Pictures share for this tutorial.

Greyhole Options 1.png

Check the option for "Uses pool" and choose the number of drives to replicate this share. In this instance we have chosen to use all drives available to the greyhole pool.

NOTE: Greyhole is not a backup solution. If a file is removed, all copies are removed.

Advanced Options

You can further configure Greyhole by manually editing /var/hda/platform/html/config/greyhole.yml.

NOTE: Options duplicated in /etc/greyhole.conf will be overridden by grehole.yml.

To see what options are available, and what they do, refer to the sample greyhole.conf provided with Greyhole.

greyhole.yml is in in YAML format. Most of it should be easy enough to modify. The only exception would be the sticky_files (and optional sticky_into) options.

Here's an example of how those should appear:

To specify the following to Greyhole in greyhole.conf:

sticky_files = Music/
 sticky_files = Videos/Movies/
     stick_into = /mnt/hdd1/gh
     stick_into = /mnt/hdd5/gh
 sticky_files = Backups/CrashPlan/
     stick_into = /mnt/hdd0/gh

one should specify this in the greyhole.yml file, where precise indentation matters:

sticky_files: 
 - - Music/
 - - Videos/Movies/
   - - /mnt/hdd1/gh
     - /mnt/hdd5/gh
 - - Backups/CrashPlan/
   - - /mnt/hdd0/gh

Once finished, it's important that you check to see the file is properly formatted. To do so, do the following:

cd /var/hda/platform/html/config
echo 'require "yaml"; YAML::load(File.open("greyhole.yml"))' | irb

If you do not see any errors, then your ready for the next step. Otherwise, ensure you correct the errors before proceeding.

For the changes to be effective, you will need to force Amahi to:

Ubuntu
Regenerate the greyhole.conf file by editing a share, clicking it's path, and just clicking the Save button without actually changing the path.
Fedora
Restart the Dashboard with any one of these alternatives as root user:
  • touch /var/hda/platform/html/tmp/restart.txt
  • systemctl restart httpd.service
  • reboot
Then regenerate the greyhole set up by changing any setting in Shares or in Drive pooling.

Tips and Best Practices

Refer to Greyhole Tips for additional guidance.

Testing and Reliability

Check out the Greyhole grinder to help make Greyhole rock solid.

References

  • Good article on Greyhole with terms explained.