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From: Adam Borowski <kilobyte@angband.pl>
To: Pintu Agarwal <pintu.ping@gmail.com>
Cc: linux-mm@kvack.org, open list <linux-kernel@vger.kernel.org>,
	kernelnewbies@kernelnewbies.org
Subject: Re: Creating compressed backing_store as swapfile
Date: Mon, 5 Nov 2018 16:58:15 +0100	[thread overview]
Message-ID: <20181105155815.i654i5ctmfpqhggj@angband.pl> (raw)
In-Reply-To: <CAOuPNLjuM5qq3go9ZFZcK0G5pQxTQb0DY36xu+8SL4vC4zJntw@mail.gmail.com>

On Mon, Nov 05, 2018 at 08:31:46PM +0530, Pintu Agarwal wrote:
> Hi,
> 
> I have one requirement:
> I wanted to have a swapfile (64MB to 256MB) on my system.
> But I wanted the data to be compressed and stored on the disk in my swapfile.
> [Similar to zram, but compressed data should be moved to disk, instead of RAM].
> 
> Note: I wanted to optimize RAM space, so performance is not important
> right now for our requirement.
> 
> So, what are the options available, to perform this in 4.x kernel version.
> My Kernel: 4.9.x
> Board: any - (arm64 mostly).
> 
> As I know, following are the choices:
> 1) ZRAM: But it compresses and store data in RAM itself
> 2) frontswap + zswap : Didn't explore much on this, not sure if this
> is helpful for our case.
> 3) Manually creating swapfile: but how to compress it ?
> 4) Any other options ?

Loop device on any filesystem that can compress (such as btrfs)?  The
performance would suck, though -- besides the indirection of loop, btrfs
compresses in blocks of 128KB while swap wants 4KB writes.  Other similar
option is qemu-nbd -- it can use compressed disk images and expose them to a
(local) nbd client.


Meow!
-- 
⢀⣴⠾⠻⢶⣦⠀ Have you heard of the Amber Road?  For thousands of years, the
⣾⠁⢰⠒⠀⣿⡁ Romans and co valued amber, hauled through the Europe over the
⢿⡄⠘⠷⠚⠋⠀ mountains and along the Vistula, from Gdańsk.  To where it came
⠈⠳⣄⠀⠀⠀⠀ together with silk (judging by today's amber stalls).

  reply	other threads:[~2018-11-05 15:58 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-05 15:01 Creating compressed backing_store as swapfile Pintu Agarwal
2018-11-05 15:58 ` Adam Borowski [this message]
2018-11-05 16:07   ` Austin S. Hemmelgarn
2018-11-05 16:14     ` valdis.kletnieks
2018-11-05 16:28       ` Austin S. Hemmelgarn
2018-11-05 16:53         ` valdis.kletnieks
2018-11-05 16:55           ` Austin S. Hemmelgarn
2018-11-08  9:51     ` Pintu Agarwal
2018-11-05 16:12 ` valdis.kletnieks
2018-11-08  9:46   ` Pintu Agarwal

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