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From: "Austin S. Hemmelgarn" <ahferroin7@gmail.com>
To: Hugo Mills <hugo@carfax.org.uk>,
	Andrei Borzenkov <arvidjaar@gmail.com>,
	kreijack@inwind.it, Duncan <1i5t5.duncan@cox.net>,
	linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 0/4] 3- and 4- copy RAID1
Date: Fri, 20 Jul 2018 14:46:42 -0400	[thread overview]
Message-ID: <ac9b68aa-0d4c-1d8c-9a5c-a5d9dda7473c@gmail.com> (raw)
In-Reply-To: <20180720184159.GD21293@carfax.org.uk>

On 2018-07-20 14:41, Hugo Mills wrote:
> On Fri, Jul 20, 2018 at 09:38:14PM +0300, Andrei Borzenkov wrote:
>> 20.07.2018 20:16, Goffredo Baroncelli пишет:
> [snip]
>>> Limiting the number of disk per raid, in BTRFS would be quite simple to implement in the "chunk allocator"
>>>
>>
>> You mean that currently RAID5 stripe size is equal to number of disks?
>> Well, I suppose nobody is using btrfs with disk pools of two or three
>> digits size.
> 
>     But they are (even if not very many of them) -- we've seen at least
> one person with something like 40 or 50 devices in the array. They'd
> definitely got into /dev/sdac territory. I don't recall what RAID level
> they were using. I think it was either RAID-1 or -10.
> 
>     That's the largest I can recall seeing mention of, though.
I've talked to at least two people using it on 100+ disks in a SAN 
situation.  In both cases however, BTRFS itself was only seeing about 20 
devices and running in raid0 mode on them, with each of those being a 
RAID6 volume configured on the SAN node holding the disks for it.  From 
what I understood when talking to them, they actually got rather good 
performance in this setup, though maintenance was a bit of a pain.

  reply	other threads:[~2018-07-20 19:36 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-13 18:46 [PATCH 0/4] 3- and 4- copy RAID1 David Sterba
2018-07-13 18:46 ` [PATCH] btrfs-progs: add support for raid1c3 and raid1c4 David Sterba
2018-07-13 18:46 ` [PATCH 1/4] btrfs: refactor block group replication factor calculation to a helper David Sterba
2018-07-13 18:46 ` [PATCH 2/4] btrfs: add support for 3-copy replication (raid1c3) David Sterba
2018-07-13 21:02   ` Goffredo Baroncelli
2018-07-17 16:00     ` David Sterba
2018-07-13 18:46 ` [PATCH 3/4] btrfs: add support for 4-copy replication (raid1c4) David Sterba
2018-07-13 18:46 ` [PATCH 4/4] btrfs: add incompatibility bit for extended raid features David Sterba
2018-07-15 14:37 ` [PATCH 0/4] 3- and 4- copy RAID1 waxhead
2018-07-16 18:29   ` Goffredo Baroncelli
2018-07-16 18:49     ` Austin S. Hemmelgarn
2018-07-17 21:12     ` Duncan
2018-07-18  5:59       ` Goffredo Baroncelli
2018-07-18  7:20         ` Duncan
2018-07-18  8:39           ` Duncan
2018-07-18 12:45             ` Austin S. Hemmelgarn
2018-07-18 12:50             ` Hugo Mills
2018-07-19 21:22               ` waxhead
2018-07-18 12:50           ` Austin S. Hemmelgarn
2018-07-18 19:42           ` Goffredo Baroncelli
2018-07-19 11:43             ` Austin S. Hemmelgarn
2018-07-19 17:29               ` Goffredo Baroncelli
2018-07-19 19:10                 ` Austin S. Hemmelgarn
2018-07-20 17:13                   ` Goffredo Baroncelli
2018-07-20 18:33                     ` Austin S. Hemmelgarn
2018-07-20  5:17             ` Andrei Borzenkov
2018-07-20 17:16               ` Goffredo Baroncelli
2018-07-20 18:38                 ` Andrei Borzenkov
2018-07-20 18:41                   ` Hugo Mills
2018-07-20 18:46                     ` Austin S. Hemmelgarn [this message]
2018-07-16 21:51   ` waxhead
2018-07-15 14:46 ` Hugo Mills
2018-07-19  7:27 ` Qu Wenruo
2018-07-19 11:47   ` Austin S. Hemmelgarn
2018-07-20 16:42     ` David Sterba
2018-07-20 16:35   ` David Sterba

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