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Old 07-27-2014, 10:58 AM   #1
jlparsons
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Unequal drives - Raid 0


Hi folks, I have a laptop which has a 256gb 2.5inch SSD and a second 16gb MSATA SSD which was originally intended as a windows caching drive (the laptop came with windows and a regular HDD). Wondering how I might use this second little SSD to speed things up.

I thought about creating two virtual partitions;

1. / mounted on a RAID0 array spanning two 16gb partitions, one taking up a small part of the 2.5inch drive and one taking up all of the MSATA drive.
2. /home mounted on a 184gb partition created on the 2.5inch SSD

Wondering if there would be much benefit from this? Both drives are equally fast on read speed but the MSATA drive's write speed is half that of the 2.5inch. Having one of the RAID drives on the same physical volume as the /home partition means that when accessing both simultaneously there will of course be a bottleneck.

Is there a more intelligent solution? Would bcache or dm-cache deliver any advantage in this scenario where both drives are effectively as fast but we have two separate physical volumes and two SATA3 connections? I guess the perfect scenario would be some form of intelligent striping where the software controller stripes the most accessed files between the larger and smaller SSDs, leaving the less often accessed files on the larger SSD unstriped. Somehow I expect this doesn't exist...

Last edited by jlparsons; 07-28-2014 at 06:47 AM.
 
Old 07-28-2014, 04:54 AM   #2
TenTenths
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Linux is much better at memory/swap management compared to windows, in practise we've not noticed any significant advantages of using an SSD for swap on a Linux laptop.
 
Old 07-28-2014, 04:59 AM   #3
jlparsons
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Quote:
Originally Posted by TenTenths View Post
Linux is much better at memory/swap management compared to windows, in practise we've not noticed any significant advantages of using an SSD for swap on a Linux laptop.
Sorry, I should have been clearer - I was looking to use the RAID/caching solution to speed up disk performance, not to use as a swap partition. I don't use a swap partition at all, I use swapspace just in case but it's never actually been needed. I'm looking for a way to use the two SSD drives with separate SATA3 connections to best effect.

Last edited by jlparsons; 07-28-2014 at 06:33 AM.
 
  


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