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Re: making more room in root partition for distribution upgrade




On Mon, 21 May 2018 21:48:33 +0200 Pascal Hambourg said:

> Le 21/05/2018 à 21:03, Abdullah Ramazanoğlu a écrit :
> > 
> > Forgot to add that in a raid-1 setup swap partition*s* should not be
> > mirrored.  
> 
> Of course they should be mirrored in RAID 1 too. Otherwise it defeats 
> the purpose of RAID 1.
> 
> > There should be 2 separate non-mirrored swap partitions, one on each drive,
> > for better swap performance (distributed I/O).  
> 
> The purpose of RAID 1 is to provide redundancy and availability, not 
> performance.
> What do you think happens to a running system when one half of the swap 
> suddenly becomes unavailable after a disk failure ?

I would agree mirroring swap for a mission critical server. Otherwise it would
be an overkill, IMO.

If one of the non-mirrored swaps go down, then I will get a system crash. So?
Estimating once in a 15 years on average I would get a head-crash, this doesn't
justify (1) wasting disk space for mirrored swap, and (2) not taking advantage
of distributed swap I/O.

Though, RAID-1 read logic (of concurrent parallel I/O) partly compensates for
(2).

As for the purpose of RAID-1, there is theory and there is practice. It boosts
I/O performance, in addition to the advantages you mentioned.

Regards
-- 
Abdullah Ramazanoğlu