Ubuntu
ubiquity package

swap for 64 Gib RAM

Asked by Alexander Jueterbock

What would you recommend as swap size for 63 Gib RAM?
I chose now 20 Gib but got unsecure because it is recommended that it shall be at least as big as the RAM itself. Does that also apply for such high memory capacities?

Thank you for any help.

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mycae
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mycae (mycae) said : 		#1

The at least as large as ram rule applies because suspend to disk (sleep) mode needs that to function reliably, as you may be using all that 63GB ram then you go to sleep (power off the ram), and need to dump the data somwhere.

Its a phenomenal amount of ram, and I wonder what on earth you are doing to need that much.

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wojox (wojox) said : 		#2

What are you running? A server? In which case it won't go to sleep so you won't even need swap.

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Alexander Jueterbock (alexander-jueterbock) said : 		#3

Thank you for your answers.
I am running Ubuntu Desktop 11.04, 64 bit. Several users can access the computer via ssh and run programs on it.
So, as far as I understand, with the actual setup, when more than 20Gb RAM are used and the computer goes into sleep mode, it can only store 20 Gb in swap and might lose data.
So I should indeed allocate 64 Gb as swap area to be on the safe site?

Thank you.

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Best mycae (mycae) said : 		#4

>So, as far as I understand, with the actual setup, when more than 20Gb RAM are used and the computer goes
>into sleep mode, it can only store 20 Gb in swap and might lose data.

It will lose state, so you probably have to reboot if you sleep it. I would simply not allocate much swap space and disable suspend mode -- particularly if users are SSH-ing in. Users will of course be unable to SSH in if the computer is suspended.

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Alexander Jueterbock (alexander-jueterbock) said : 		#5

Thanks mycae, that solved my question.