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From: "Austin S. Hemmelgarn" <ahferroin7@gmail.com>
To: Roman Mamedov <rm@romanrm.net>,
	Marco Lorenzo Crociani <marcoc@prismatelecomtesting.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: mount time for big filesystems
Date: Thu, 31 Aug 2017 07:45:55 -0400	[thread overview]
Message-ID: <d4214656-ec36-4a1e-7c4d-a528c0ae61be@gmail.com> (raw)
In-Reply-To: <20170831163656.6be88191@natsu>

On 2017-08-31 07:36, Roman Mamedov wrote:
> On Thu, 31 Aug 2017 12:43:19 +0200
> Marco Lorenzo Crociani <marcoc@prismatelecomtesting.com> wrote:
> 
>> Hi,
>> this 37T filesystem took some times to mount. It has 47
>> subvolumes/snapshots and is mounted with
>> noatime,compress=zlib,space_cache. Is it normal, due to its size?
> 
> If you could implement SSD caching in front of your FS (such as lvmcache or
> bcache), that would work wonders for performance in general, and especially
> for mount times. I have seen amazing results with lvmcache (of just 32 GB) for
> a 14 TB FS.
If you use dm-cache (what LVM uses), you need to be _VERY_ careful and 
can't use it safely at all with multi-device volumes because it leaves 
the underlying block device exposed.
> 
> As for in general, with your FS size perhaps you should be using
> "space_cache=v2" for better performance, but I'm not sure if that will have
> any effect on mount time (aside from slowing down the first mount with that).
It shouldn't have any other impact on mount time, but it may speed up 
other operations.

  reply	other threads:[~2017-08-31 11:46 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31 10:43 mount time for big filesystems Marco Lorenzo Crociani
2017-08-31 11:00 ` Hans van Kranenburg
2017-08-31 11:22   ` Austin S. Hemmelgarn
2017-08-31 11:36 ` Roman Mamedov
2017-08-31 11:45   ` Austin S. Hemmelgarn [this message]
2017-08-31 12:16     ` Roman Mamedov
2017-08-31 14:13   ` Qu Wenruo
2017-09-01 13:52   ` Juan Orti Alcaine
2017-09-01 13:59     ` Austin S. Hemmelgarn
     [not found]       ` <CAC+fKQWFbdF6b3jGO_6hG_pNNzKobBYMeSNyEi5XRCf5YKa81Q@mail.gmail.com>
2017-09-01 15:20         ` Austin S. Hemmelgarn
2017-09-01 22:41           ` Dan Merillat

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