Gentoo Archives: gentoo-user

From: Wol <antlists@××××××××××××.uk>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] External hard drive and idle activity
Date: Fri, 03 Jan 2020 00:43:12
Message-Id: f364e3aa-44ba-c99c-2d67-ac09eab2509f@youngman.org.uk
In Reply to: Re: [gentoo-user] External hard drive and idle activity by Rich Freeman
1 On 02/01/2020 19:12, Rich Freeman wrote:
2 > For reads they're completely normal. For sequential writes to unused
3 > space they're completely normal. For random writes or overwrites they
4 > are significantly different from traditional hard drives.
5
6 That's why the "S" stands for "shingled" (which means "overlapped",
7 think of a shingled roof - which is your normal overlapping tile jobbie).
8
9 The point of a shingled drive is that it has a narrow read head - let's
10 call it one unit wide. But a write head is larger, lets call it three
11 units wide. If each track is one unit wide - the correct size to be read
12 - then writing a track will destroy two tracks.
13
14 So the write head lays down data in concentric rings, and CAN'T
15 overwrite data - it has to wipe everything and rewrite it. So as
16 mentioned before you really do not want these drives for random writes -
17 think of them as a bit like a random-write tape drive ie you can get
18 away with it but you're better off not trying.
19
20 And yes - the 8TB capacity gave it away - I think the largest "normal"
21 drives available are 4TB at present ... anything bigger must be shingled.
22
23 Cheers,
24 Wol

Replies

Subject Author
Re: [gentoo-user] External hard drive and idle activity Rich Freeman <rich0@g.o>