From: Tim Walberg <twalberg@comcast.net>
To: Austin S Hemmelgarn <ahferroin7@gmail.com>
Cc: Duncan <1i5t5.duncan@cox.net>, linux-btrfs@vger.kernel.org
Subject: Re: Expected behavior of bad sectors on one drive in a RAID1
Date: Tue, 20 Oct 2015 15:54:38 -0500 [thread overview]
Message-ID: <20151020205438.GC4598@comcast.net> (raw)
In-Reply-To: <56269D1C.5080006@gmail.com>
On 10/20/2015 15:59 -0400, Austin S Hemmelgarn wrote:
>> .........
>> With a 32-bit checksum and a 4k block (the math is easier with
>> smaller numbers), that's 4128 bits, which means that a random
>> single bit error will have a approximately 0.24% chance of
>> occurring in a given bit, which translates to an approximately
>> 7.75% chance that it will occur in one of the checksum bits. For a
>> 16k block it's smaller of course (around 1.8% I think, but that's
>> just a guess), but it's still sufficiently statistically likely
>> that it should be considered.
>> .........
Last I checked, a 4 kilo-BYTE block consisted of 32768 BITs... So the
percentages should in fact be considerably smaller than that.
--
twalberg@gmail.com
next prev parent reply other threads:[~2015-10-20 21:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 4:16 Expected behavior of bad sectors on one drive in a RAID1 james harvey
2015-10-20 4:45 ` Russell Coker
2015-10-20 13:00 ` Austin S Hemmelgarn
2015-10-20 13:15 ` Russell Coker
2015-10-20 13:59 ` Austin S Hemmelgarn
2015-10-20 19:20 ` Duncan
2015-10-20 19:59 ` Austin S Hemmelgarn
2015-10-20 20:54 ` Tim Walberg [this message]
2015-10-21 11:51 ` Austin S Hemmelgarn
2015-10-21 12:07 ` Austin S Hemmelgarn
2015-10-21 16:01 ` Chris Murphy
2015-10-21 17:28 ` Austin S Hemmelgarn
2015-10-20 18:54 ` Duncan
2015-10-20 19:48 ` Austin S Hemmelgarn
2015-10-20 21:24 ` Duncan
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