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Change defect drive in RAID 5. Hotswap "live" or shut down - swap- turn on?

Hi.
Have a HP ML 350G6 with a P410i Raid controller and 3 x 146 GB hotswap SAS drives.
One is defect.

Have swap theese drives many times  (have many customers with this server type)
Some times hot-swapped while server is running and checked in Array config util that all is good.
And other times, I have shut the server down and swapped.

One way better\ safer than the other?
Thanx
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Elmar KoschkaSenior System Engineer
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Commented:
I never shut down a server to change a hotswap drive. for me is the safer way. Its a feeling. But there`s no difference between this two alternative.
HOTSWAP means replacing the components with out any interruption to the system. Hence the hotswap is the preferred method if the components supports the feature.
Commented:
Hi.
As long as I m sure about the raid configuration (that is 5 or 1, or 10) I always did it with the server on.
Practically the raid card is going to do exactly the same thing either the server is on or starting up.
There is no difference between the two alternatives.
here is a link to wikipedia regarding the hot swapping of disks for more references.
http://en.wikipedia.org/wiki/Hot_swapping
Stephen McTigueAssistant Director of Information Technology
Commented:
I find the best method if it's a hot swap drive is to change the drive while the server is running so the drives can immediately start rebuilding and you know the data is still accessible.

Otherwise, it may take some time to access the server if you change the drive while it's powered off, since the drives will start to rebuild soon after the system is restarted. This may affect access to the server.
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Distinguished Expert 2019
Commented:
Shutting down is not advised since it can confuse the controller as to what's the replacement drive and what has the data on it. If you plug in live the controller knows to ignore what's on the disk.
Tore JacobsenSystem adminstrator

Author

Commented:
Thank you all
Andrew DavisManager

Commented:
given that everything is good, either method is good. But my personal preference is to always do hot swap where i can as it is better for the end users. Having said that i ALLWAYS ensure that i have a current up to date and verified backup.

Reason
during a rebuild the drives must work hard to rebuild the data, so it stands to reason that if you have a second drive about to fail this is going to stress test it, and should it fail while the first is rebuilding then you now have a dead array (depending on the type of array, but assume raid 5 as mentioned in header). My backups are incremental so they will not wqork the drive nearly as hard as a rebuild, and then i have piece of mind. also remember that if you are doing this during working hours then changes since the backup will be lost, and regardless of that the rebuild will have a performance hit on the array so i allways leave it till the quietest time to put the new drive in and let the rebuild do it thing.

cheers
Andrew

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