From: Goffredo Baroncelli <kreijack@libero.it>
To: Graham Cobb <g.btrfs@cobb.uk.net>, linux-btrfs@vger.kernel.org
Subject: Re: [RFC][PATCH V3] btrfs: ssd_metadata: storing metadata on SSD
Date: Sun, 5 Apr 2020 20:47:15 +0200 [thread overview]
Message-ID: <4f10882a-fa89-25e0-901c-aff8010d46cd@libero.it> (raw)
In-Reply-To: <58e315a1-0307-9a26-8fb4-fd5220c1d5a6@cobb.uk.net>
On 4/5/20 12:57 PM, Graham Cobb wrote:
> On 05/04/2020 09:26, Goffredo Baroncelli wrote:
[...]
>>
>>
>> Test description real (mmm:ss) Delta %
>> -------------------- ------------- -------
>> btrfs hdd w/sync 142:38 +533%
>> btrfs ssd+hdd w/sync 81:04 +260%
>> ext4 hdd w/sync 52:39 +134%
>> btrfs bcache w/sync 35:59 +60%
>> btrfs ssd w/sync 22:31 reference
>> ext4 ssd w/syn 12:19 -45%
>
> Interesting data but it seems to be missing the case of btrfs ssd+hdd
> w/sync without your patch in order to tell what difference your patch
> made. Or am I confused?
>
Currently BTRFS allocates the chunk on the basis of the free space.
For my tests I have a smaller ssd (20GB) and a bigger hdd (230GB).
This means that the latter has higher priority for the allocation,
until the free space became equal.
The rationale behind my patch is the following:
- is quite simple (even tough in 3 iteration I put two errors :-) )
- BTRFS has already two kind of information to store: data and metadata.
The former is (a lot ) bigger, than the latter. Having two kind of storage,
one faster (and expensive) than the other, it is natural to put the metadata
in the faster one, and the data in the slower one.
BR
G.Baroncelli
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
next prev parent reply other threads:[~2020-04-05 18:47 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-05 8:26 [RFC][PATCH V3] btrfs: ssd_metadata: storing metadata on SSD Goffredo Baroncelli
2020-04-05 8:26 ` [PATCH] btrfs: add ssd_metadata mode Goffredo Baroncelli
2020-04-14 5:24 ` Paul Jones
2020-10-23 7:23 ` Wang Yugui
2020-10-23 10:11 ` Adam Borowski
2020-10-23 11:25 ` Qu Wenruo
2020-10-23 12:37 ` Wang Yugui
2020-10-23 12:45 ` Qu Wenruo
2020-10-23 13:10 ` Steven Davies
2020-10-23 13:49 ` Wang Yugui
2020-10-23 18:03 ` Goffredo Baroncelli
2020-10-24 3:26 ` Paul Jones
2020-04-05 10:57 ` [RFC][PATCH V3] btrfs: ssd_metadata: storing metadata on SSD Graham Cobb
2020-04-05 18:47 ` Goffredo Baroncelli [this message]
2020-04-05 21:58 ` Adam Borowski
2020-04-06 2:24 ` Zygo Blaxell
2020-04-06 16:43 ` Goffredo Baroncelli
2020-04-06 17:21 ` Zygo Blaxell
2020-04-06 17:33 ` Goffredo Baroncelli
2020-04-06 17:40 ` Zygo Blaxell
2020-05-29 16:06 ` Hans van Kranenburg
2020-05-29 16:40 ` Goffredo Baroncelli
2020-05-29 18:37 ` Hans van Kranenburg
2020-05-30 4:59 ` Qu Wenruo
2020-05-30 6:48 ` Goffredo Baroncelli
2020-05-30 8:57 ` Paul Jones
2020-04-27 15:06 Torstein Eide
2020-04-28 19:31 ` Goffredo Baroncelli
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