Hi, I want to replace my current 3 disk "2-parity" with a single larger hdd. What is the best practice?
Current config:
parity P:\snapraid.parity,Q:\snapraid.parity
2-parity R:\snapraid.2-parity,S:\snapraid.2-parity,T:\snapraid.2-parity <<<< Want to replace this parity with single large disk
Option1
i) create 3-parity
ii) remove 2-parity
iiI) rename 3-parity to 2-parity (i.e. change conf and rename parity files)
From the FAQ:
"If you wish to remove a parity, you can simply remove the highest "N-parity" option from the configuration and then delete the parity file."
Does this mean option 1 is not possible this it is not removing the highest "N-parity"?
Last edit: alabama 2018-06-03
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I am not sure, but since splitted parity ist just an extension from one file to another, maybe it is possible to copy the three files into a single parity file, which should than work as 2-parity. maybe this does not work because SnapRAID internally knowns still, that the parity is splitted.
if this is not working, you could remove just the three discs and replace it with the new one, and then run SnapRAID to recover (in this case the parity disc). See the FAQ.
Last edit: Walter Tuppa 2018-06-03
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I wasn't confident moving the 3 files to the new drive works, I've not seen it suggested in the FAQ or forum (till now). Also all files are named the same so I've to figure a way to rename them. Not sure what other impact there might be.
Walter, you are suggesting that I treat the 2-parity as failed, remove them from the conf, add the new empty drive then run "snapraid fix -d PARITY_NAME". Correct?
That would work however I'm wondering if this is the best practice as my data would be reduced to single parity while snapraid is creating the new 2-parity. Is there a process which allows me to maintain (at least) dual parity at all times during the upgrade?
Last edit: alabama 2018-06-03
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Rename the parity-2 files so that they have unique file names like this:
R:\snapraid.2a-parity
S:\snapraid.2b-parity
T:\snapraid.2c-parity
Copy all three files to new larger parity disk (let's pretend it is X:)
Update config like this:
2-parity X:\snapraid.2a-parity,X:\snapraid.2b-parity,X:\snapraid.2c-parity
Done
There is no technical downside to have 3 parity files on the same disk as long as they belong to the same parity level. Only one will be accessed at any time and the last one is the one that will grow if needed.
Last edit: Leifi Plomeros 2018-06-03
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Sorry for reviving an old thread. I found myself having to replace multiple parity with a single large parity, again.
Do I run a "check" after to verify the new parity drive is 100% correct?
Also, would I be able to apply a disk filter so only the new parity disk is "checked"? In the docs, it says I can filter a data drive but no mention if filtering parity drive works.
Thanks in advance!
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You can have up to 6 levels of parity.
Normally each parity is a single file but it can also be split up to into smaller parts using the split parity function.
snapraid check -d parity will check the first parity regardless if it is one or many files.
snapraid check -d 2-parity will check the second parity regardless if it is one or many files.
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In my case, I'm migrating 2 levels of parity, one level at a time so will execute "snapraid check -d parity" after migrating the first level of parity to new drives, then "snapraid check -d 2-parity" after migrating the second level of parity to new drives.
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Hi, I want to replace my current 3 disk "2-parity" with a single larger hdd. What is the best practice?
Current config:
parity P:\snapraid.parity,Q:\snapraid.parity
2-parity R:\snapraid.2-parity,S:\snapraid.2-parity,T:\snapraid.2-parity <<<< Want to replace this parity with single large disk
Option1
i) create 3-parity
ii) remove 2-parity
iiI) rename 3-parity to 2-parity (i.e. change conf and rename parity files)
Option2
i) create 3-parity
ii) swap 2-parity & 3-parity (i.e. change conf and rename parity files)
iii) remove 3-parity (previously 2-parity disks)
Option3 - something else?
From the FAQ:
"If you wish to remove a parity, you can simply remove the highest "N-parity" option from the configuration and then delete the parity file."
Does this mean option 1 is not possible this it is not removing the highest "N-parity"?
Last edit: alabama 2018-06-03
I am not sure, but since splitted parity ist just an extension from one file to another, maybe it is possible to copy the three files into a single parity file, which should than work as 2-parity. maybe this does not work because SnapRAID internally knowns still, that the parity is splitted.
if this is not working, you could remove just the three discs and replace it with the new one, and then run SnapRAID to recover (in this case the parity disc). See the FAQ.
Last edit: Walter Tuppa 2018-06-03
I wasn't confident moving the 3 files to the new drive works, I've not seen it suggested in the FAQ or forum (till now). Also all files are named the same so I've to figure a way to rename them. Not sure what other impact there might be.
Walter, you are suggesting that I treat the 2-parity as failed, remove them from the conf, add the new empty drive then run "snapraid fix -d PARITY_NAME". Correct?
That would work however I'm wondering if this is the best practice as my data would be reduced to single parity while snapraid is creating the new 2-parity. Is there a process which allows me to maintain (at least) dual parity at all times during the upgrade?
Last edit: alabama 2018-06-03
Rename the parity-2 files so that they have unique file names like this:
R:\snapraid.2a-parity
S:\snapraid.2b-parity
T:\snapraid.2c-parity
Copy all three files to new larger parity disk (let's pretend it is X:)
Update config like this:
2-parity X:\snapraid.2a-parity,X:\snapraid.2b-parity,X:\snapraid.2c-parity
Done
There is no technical downside to have 3 parity files on the same disk as long as they belong to the same parity level. Only one will be accessed at any time and the last one is the one that will grow if needed.
Last edit: Leifi Plomeros 2018-06-03
Fascinating! I will go down the 3 file parity path in that case.
Thank you Lefi and Walter for your valuable input!
Sorry for reviving an old thread. I found myself having to replace multiple parity with a single large parity, again.
Do I run a "check" after to verify the new parity drive is 100% correct?
Also, would I be able to apply a disk filter so only the new parity disk is "checked"? In the docs, it says I can filter a data drive but no mention if filtering parity drive works.
Thanks in advance!
Yes, you can run snapraid check -d parity to only check the first level of parity.
Cheers Leifi for the confirmation! Could you clarify what you specifically mean by "first level" of parity? Just in case I missed out on a fine point.
Cheers Leifi for the confirmation! Could you clarify what you specifically mean by "first level" of parity? Just in case I missed out on a fine point.
You can have up to 6 levels of parity.
Normally each parity is a single file but it can also be split up to into smaller parts using the split parity function.
snapraid check -d parity will check the first parity regardless if it is one or many files.
snapraid check -d 2-parity will check the second parity regardless if it is one or many files.
Understood 100%, thanks Leifi.
In my case, I'm migrating 2 levels of parity, one level at a time so will execute "snapraid check -d parity" after migrating the first level of parity to new drives, then "snapraid check -d 2-parity" after migrating the second level of parity to new drives.