Gentoo Archives: gentoo-user

From: Jarry <jarry@×××.net>
To: gentoo-user@l.g.o
Subject: [gentoo-user] mdadm --create: very low speed on formated disk
Date: Mon, 28 Aug 2006 18:37:16
1 Hi,
3 I'm creating /dev/md's for my server with:
4 mdadm --create --verbose /dev/md0
5 --level=1 --raid-devices=2
6 /dev/sda1 /dev/sdb1
8 and I have noticed following thing:
10 Whenever I create /dev/md0 on a "clean" (not previously
11 formated) disk, the syncing speed is high (30-40MB/s,
12 as shown by "cat /proc/mdstat".
14 But when I try to create raid array on partitions which
15 have been previously formated (there remained old ext3
16 formating), syncing speed is not higher than 2-3MB/s
17 (~15 hours syncing my 160 GB drives!!!).
19 One more thing: if I delete all partitions, and then write
20 them back again exactly as they were previously, it doesn't
21 help. But if I shift all partitions just 1 sector up
22 (or down), mdadm is again syncing with full speed...
24 Question: how can I sync with full speed, even if
25 there are partitions previously used and formated
26 and I do not want (or can not) move partitions?
28 Jarry
29 --
30 gentoo-user@g.o mailing list