Difference between revisions of "Greyhole landing zone"

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Important things you have to know about the “LZ” (Greyhole Landing Zone)
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''Important things you have to know about the Greyhole Landing Zone (LZ).'
  
When you are going to use Greyhole as a disk-pooling service, you have to keep a few important things in mind. Standard in the Fedora/Amahi install guide there is a small partition for “/”
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When you are going to use Greyhole as a disk-pooling service, you have to keep a few important things in mind.
(root aka System) like 20GB, recommendation for this size is bigger, but depends on the file batch size that is common for you to copy or move at the same time to you HDA-Pool (greyhole)
 
  
All data you copy to your HDA will first “Land” into your LZ (Greyhole Landing Zone) witch is located on "/" (root / System partition/drive) as default setting. From there on it will be spread out over you "Pool" shown as the example:
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The Amahi install guide suggest a small (20GB) root partition (also called system partition, or simply /).
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While this is enough for most Linux systems, on Amahi with Greyhole, this partition is used as a ''landing zone'' for new files you copy onto your shares.
  
[[Image:GreyHoleLandingZone.png]]
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All the data you copy to your HDA's shares will first ''land'' into your LZ, which is by default located in /var/hda/files/share_name.
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Those folders are used as a temporary location for new files, which will be moved into the pooled drives as soon as possible by the Greyhole service, which runs in background.
  
Basically to avoid problems in the future and keep it simple, there are two things to configure:
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Here's a schema presenting the data flow for new files added to your HDA's shares:
  
#. Make your "/" (System Partition / Drive) as big as the largest chunk of data that you copy/move to your HDA at a regular base.
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[[Image:GreyHoleLandingZone.png]]
#. Don’t include your “/” (Root /System Partition/ Drive) into you Greyhole Pool!
 
 
 
=How does it Work =
 
  
When you start the copy/move process from a client device (pc, laptop or such) Samba and Greyhole welcomes your data into the storage pool.
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== Recommendations ==
  
From there Greyhole looks where it has to go (disks with space) and how many copy's it should make of the data (preferences from the HDA Dashboard) if your que is empty (watch Greyhole commands how to see) it immateriality starts to copy the data out of you LZ to its final destination, if not it will be at the back of the existing que.
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# Pick a big enough LZ partition that will allow you to copy enough data. Choosing the biggest drives you have is usually best.
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# Move the LZ from the root partition to the location you picked. That way, if the LZ ever gets filled, it won't affect the rest of your system.
  
Meanwhile it is still receiving your data in the LZ and filling up the que with final destinations and number of copy's. This means that it does 2 things on one disk at once : 1. writing data into the LZ, 2. moving data to it's final destination on the disks present in your pool witch contains enough space. All of the locations are being stored in a SQL database witch Samba uses to locate your data when u request it.
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The Greyhole wiki documents [http://code.google.com/p/greyhole/wiki/MovingLandingZone how to relocate your LZ].
  
Of course there are more options for configuring your LZ, more details about this you can find in the [[Greyhole]] page, but is recommend for experienced users.
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If you'd like to learn more about how Greyhole uses the LZ, or just how it works, the Greyhole wiki has [http://code.google.com/p/greyhole/wiki/HowGreyholeWorks more detailed information].

Revision as of 00:49, 23 March 2011

Important things you have to know about the Greyhole Landing Zone (LZ).'

When you are going to use Greyhole as a disk-pooling service, you have to keep a few important things in mind.

The Amahi install guide suggest a small (20GB) root partition (also called system partition, or simply /). While this is enough for most Linux systems, on Amahi with Greyhole, this partition is used as a landing zone for new files you copy onto your shares.

All the data you copy to your HDA's shares will first land into your LZ, which is by default located in /var/hda/files/share_name. Those folders are used as a temporary location for new files, which will be moved into the pooled drives as soon as possible by the Greyhole service, which runs in background.

Here's a schema presenting the data flow for new files added to your HDA's shares:

GreyHoleLandingZone.png

Recommendations

  1. Pick a big enough LZ partition that will allow you to copy enough data. Choosing the biggest drives you have is usually best.
  2. Move the LZ from the root partition to the location you picked. That way, if the LZ ever gets filled, it won't affect the rest of your system.

The Greyhole wiki documents how to relocate your LZ.

If you'd like to learn more about how Greyhole uses the LZ, or just how it works, the Greyhole wiki has more detailed information.