From: luvar@plaintext.sk
To: linux-btrfs@vger.kernel.org
Subject: btrfs deduplication and linux cache management
Date: Thu, 30 Oct 2014 10:26:07 +0100 (GMT+01:00) [thread overview]
Message-ID: <650272300.271414661167523.JavaMail.root@shiva> (raw)
In-Reply-To: <1589590871.231414660858286.JavaMail.root@shiva>
Hi,
I want to ask, if deduplicated file content will be cached in linux kernel just once for two deduplicated files.
To explain in deep:
- I use btrfs for whole system with few subvolumes with some compression on some subvolumes.
- I have two directories with eclipse SDK with slightly differences (same version, different config)
- I assume that given directories is deduplicated and so two eclipse installations take place on hdd like one would (in rough estimation)
- I will start one of given eclipse
- linux kernel will cache all opened files during start of eclipse (I have enough free ram)
- I am just happy stupid linux user:
1. will kernel cache file content after decompression? (I think yes)
2. cached data will be in VFS layer or in block device layer?
- When I will lunch second eclipse (different from first, but deduplicated from first) after first one:
1. will second start require less data to be read from HDD?
2. will be metadata for second instance read from hdd? (I asume yes)
3. will be actual data read second time? (I hope not)
Thanks for answers,
have a nice day,
--
LuVar
next parent reply other threads:[~2014-10-30 9:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1589590871.231414660858286.JavaMail.root@shiva>
2014-10-30 9:26 ` luvar [this message]
2014-10-30 12:00 ` btrfs deduplication and linux cache management Austin S Hemmelgarn
2014-10-30 16:00 ` Zygo Blaxell
2014-11-03 14:09 ` LuVar
2014-11-04 20:01 ` Zygo Blaxell
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