Best way to increase storage in raid 6

alex1002

Member
Apr 9, 2013
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Good day,
Currently I have a raid 6 with 6*4tb harrd drives. I am running low on storage. I got 6*8tb hard drives coming. What's the best way for me to approach this.
1.pull one drive and rebuild, till I replace all six. Then increase space.
Is there better ways.
Thank you

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ttabbal

Active Member
Mar 10, 2016
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Since this is the hardware RAID section, which controller are you using? The options might be different from one model to the next.
 

i386

Well-Known Member
Mar 18, 2016
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1.pull one drive and rebuild, till I replace all six. Then increase space.
I think this will take forever as you have to do this in two steps:
First you have to rebuild 6x 4tb (of 8tb) of the array. During the rebuilding the controller (usually*) disables all volatile cache, making this whole process extreme slow. With 4tb to rebuild my guesss is that it will take about 8-9 days per replaced hdd. -> 6*9days = 54 days.
Second you have to do the online capacity expansion, this will take probably 14-21 days with 8tb drives.
In the worst case you will have to wait about 65 days for more storage capacity.

*Adaptec controller do this (but you can override the settings and enable controller and hdd cache at your own risk), I am not sure how the LSI controllers handle this.


I would get another controller (or a cheap sas2/3 expander) and create a new array with the 6x 8tb drives.
But this is only possible if your budget and current chassis allow it.
 

alex1002

Member
Apr 9, 2013
518
18
18
I think this will take forever as you have to do this in two steps:
First you have to rebuild 6x 4tb (of 8tb) of the array. During the rebuilding the controller (usually*) disables all volatile cache, making this whole process extreme slow. With 4tb to rebuild my guesss is that it will take about 8-9 days per replaced hdd. -> 6*9days = 54 days.
Second you have to do the online capacity expansion, this will take probably 14-21 days with 8tb drives.
In the worst case you will have to wait about 65 days for more storage capacity.

*Adaptec controller do this (but you can override the settings and enable controller and hdd cache at your own risk), I am not sure how the LSI controllers handle this.


I would get another controller (or a cheap sas2/3 expander) and create a new array with the 6x 8tb drives.
But this is only possible if your budget and current chassis allow it.
I have spare cards but this case only takes 6 drives.

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EffrafaxOfWug

Radioactive Member
Feb 12, 2015
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Assume you don't have another server or a backup you can restore from onto a fresh array? If you've got the time and patience to do it by replacing one drive at a time you can, or if you're prepared to risk your data you can do it with copying to temporary storage:

You've currently got a ~14TB array - buy a USB/eSATA/whatever connector and copy data off the current array on to two of the new 8TB drives
Build a new RAID array (assuming RAID6 again?) out of the remaining four 8TB drives, which'll give you a ~14TB array
Copy data back from the single discs on to the fresh array
Once the copies are done, you can incorporate the new drives into your array at your leisure - although rebuild/expansion times will be huge
 

msg7086

Active Member
May 2, 2017
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If you can risk your data and you have a spare port:

1. Split and copy your data onto your 2x8TB drives; <- you can use 4x drives and copy twice to make redundancy.
2. Break the array apart and copy your data back to 4x4TB drives; <- if you have spare drives to make 32TB, you can still keep 2 copies.
3. Set up your 6x8TB array;
4. Copy your data onto your new array from 4TB drives.

Assuming 120MB/s copying speed, the whole process should complete within a week or two.