Gentoo Archives: gentoo-user

From: Volker Armin Hemmann <volkerarmin@××××××××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Normal disk speed?
Date: Thu, 30 Sep 2010 16:53:45
Message-Id: 201009301853.28825.volkerarmin@googlemail.com
In Reply to: [gentoo-user] Normal disk speed? by Adam Carter
1 On Thursday 30 September 2010, Adam Carter wrote:
2 > Taring my mp3 collection from 2.5in 500MB internal sata drive (sda) to
3 > esata 3.5in 500MB drive (sdb) and it seems slow. In vmstat i can see that
4 > the external drive writes faster than the internal can read (external has
5 > periods of inactivity)
6 > # time tar cf /mnt/usbdrive/mp3back.tar mp3/
7 >
8 > real 10m9.679s
9 > user 0m1.577s
10 > sys 2m1.769s
11 > # du -ks mp3/
12 > 21221661 mp3/
13 >
14 > So 21221MB in 610 seconds = 35 MB/s
15 >
16 > # hdparm -t /dev/sda
17 >
18 > /dev/sda:
19 > Timing buffered disk reads: 220 MB in 3.01 seconds = 73.14 MB/sec (77
20 > with --direct)
21 >
22 > FWIW;
23 > # hdparm /dev/sda
24 >
25 > /dev/sda:
26 > multcount = 16 (on)
27 > IO_support = 1 (32-bit)
28 > readonly = 0 (off)
29 > readahead = 256 (on)
30 > geometry = 60801/255/63, sectors = 976773168, start = 0
31 >
32 >
33 > So the should i expect filesystem (reiser3) and other overhead to cut the
34 > read performance to less than half of what hdparm reports? Anything else i
35 > can look at to speed it up? Im using CFQ io scheduler.
36
37 as soon as your harddisk seeks you are lucky to be above 5mb/sec. Yes, even
38 with a modern harddrive. Just look up the seek times and do the math.
39
40 Your harddisk seeks, everything is slow.

Replies

Subject Author
Re: [gentoo-user] Normal disk speed? Adam Carter <adamcarter3@×××××.com>