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Hi!
I have a problem with my RAID, I try to set up this for the first time and when I try to create a new raid I have a message:
$ mdadm --create /dev/md1 --level=0 --raid-devices=2 /dev/sdb /dev/sdc
mdadm: cannot open /dev/sdb: Device or resource busyand:
# cat /proc/mdstat
Personalities : [raid0]
md127 : inactive sdb1[0](S)
101376 blocks super 1.2
unused devices: <none>How to fix this?
Thanks for help
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seems like mdadm thinks sdb1 is already part of a RAID for some reason, try
mdadm --stop /dev/md127And are you sure you want to use sdb/sdc instead of sdb1/sdc1 when creating the RAID? Not sure if this even works, you usually use partitions instead of the disk itself.
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OK, now it works, I've got something like this:
UWAGA: Na '/dev/sdc' wykryto tablicę partycji GPT (GUID Partition Table)! fdisk nie obsługuje GPT. Należy użyć GNU Parteda.
Dysk /dev/sdc: 82.3 GB, bajtów: 82347195904
głowic: 256, sektorów/ścieżkę: 63, cylindrów: 9972, w sumie sektorów: 160834367
Jednostka = sektorów, czyli 1 * 512 = 512 bajtów
Rozmiar sektora (logiczny/fizyczny) w bajtach: 512 / 512
Rozmiar we/wy (minimalny/optymalny) w bajtach: 512 / 512
Identyfikator dysku: 0x00000000
Urządzenie Rozruch Początek Koniec Bloków ID System
/dev/sdc1 1 160834366 80417183 ee GPT
UWAGA: Na '/dev/sdb' wykryto tablicę partycji GPT (GUID Partition Table)! fdisk nie obsługuje GPT. Należy użyć GNU Parteda.
Dysk /dev/sdb: 82.3 GB, bajtów: 82347195904
głowic: 256, sektorów/ścieżkę: 63, cylindrów: 9972, w sumie sektorów: 160834367
Jednostka = sektorów, czyli 1 * 512 = 512 bajtów
Rozmiar sektora (logiczny/fizyczny) w bajtach: 512 / 512
Rozmiar we/wy (minimalny/optymalny) w bajtach: 512 / 512
Identyfikator dysku: 0x00000000
Urządzenie Rozruch Początek Koniec Bloków ID System
/dev/sdb1 1 160834366 80417183 ee GPT
Dysk /dev/md0: 164.7 GB, bajtów: 164689346560
głowic: 2, sektorów/ścieżkę: 4, cylindrów: 40207360, w sumie sektorów: 321658880
Jednostka = sektorów, czyli 1 * 512 = 512 bajtów
Rozmiar sektora (logiczny/fizyczny) w bajtach: 512 / 512
Rozmiar we/wy (minimalny/optymalny) w bajtach: 524288 / 1048576
Identyfikator dysku: 0x00000000
Urządzenie Rozruch Początek Koniec Bloków ID System
/dev/md0p1 4 321658879 160829438 83 Linux
Partycja 1 nie zaczyna się na granicy bloku fizycznego.and this is raid0, so the speed have to be increase, but when I put this:
# hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 138 MB in 3.05 seconds = 45.26 MB/secand:
hdparm -t /dev/sdb
/dev/sdb:
Timing buffered disk reads: 158 MB in 3.03 seconds = 52.12 MB/sechdparm -t /dev/sdc
/dev/sdc:
Timing buffered disk reads: 158 MB in 3.00 seconds = 52.60 MB/secBefore raid0 installation the disk speed was 80 MB/s each
Why is that?
Thanks for reply
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Perhaps you need to run ....hdparm... on partitions rather than full discs since that may cause slow downs due to access time.
Prediction...This year will be a very odd year!
Hard work does not kill people but why risk it: Charlie Mccarthy
A man is not complete until he is married..then..he is finished.
When ALL is lost, what can be found? Even bytes get lonely for a little bit! X-ray confirms Iam spineless!
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# hdparm -t /dev/sdb
/dev/sdb:
Timing buffered disk reads: 158 MB in 3.03 seconds = 52.12 MB/sec
# hdparm -t /dev/sdc
/dev/sdc:
Timing buffered disk reads: 158 MB in 3.00 seconds = 52.60 MB/sec
# hdparm -t /dev/sdb1
/dev/sdb1:
Timing buffered disk reads: 174 MB in 3.02 seconds = 57.59 MB/sec
# hdparm -t /dev/sdc1
/dev/sdc1:
Timing buffered disk reads: 174 MB in 3.03 seconds = 57.35 MB/sec
# hdparm -t /dev/md0p1
/dev/md0p1:
Timing buffered disk reads: 172 MB in 3.01 seconds = 57.10 MB/secI don't know it's important, but I created the partition md0p1 on RAID0 using cfdisk not lvm, then I make ext4 file system on it.
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I test my disk by dd and I think it shows results properly.
To close, thanks for reply.
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Perhaps cat /proc/mdstat....will give you helpful info regarding your raid0...assuming you are using mdadm software.
The results you display indicate a raid1 arrangement AFAICT.
Prediction...This year will be a very odd year!
Hard work does not kill people but why risk it: Charlie Mccarthy
A man is not complete until he is married..then..he is finished.
When ALL is lost, what can be found? Even bytes get lonely for a little bit! X-ray confirms Iam spineless!
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As you wish:
Personalities : [raid0]
md0 : active raid0 sdc1[1] sdb1[0]
160829440 blocks super 1.2 512k chunks
unused devices: <none>Offline
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