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#1 2011-12-07 03:00:06

lilsirecho
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Registered: 2003-10-24
Posts: 5,000

[root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

The subject of this post is raid0 expansion or "grow" which is described in the wiki as the method to do the expansion.

However, in latest kernel upgrades the method fails.

[root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2
mdadm: /dev/md0: could not set level to raid4
As is shown the interim raid4 necessary to perform the sync operation is not allowed.

What can be done to enable added /devices to an existing array without requiring a new create statement?

It might well be a good idea to have a separate raid array indexed thread to consolidate all the raid problems in one arena.


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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#2 2011-12-07 07:37:12

kurych
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From: Saint-Petersburg, Russia
Registered: 2011-12-07
Posts: 27

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Can you show us output "cat /proc/mdstat"?

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#3 2011-12-07 15:46:17

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

The following is the file for /dev/md0:

[root@n6re ~]# cat /proc/mdstat
Personalities : [raid0] [raid6] [raid5] [raid4] 
md0 : active raid0 sdb2[0] sda2[1]
      15588864 blocks super 1.2 512k chunks
      
unused devices: <none>
[root@n6re ~]# 

There is no indication of a third device in this file because it was not added by the --add procedure which failed.

EDIT:  The array /dev/md0 is ~15GB and is bootable thru partitioned boot.  The array /dev/md0 is partition#2 of the two drives and serves as root in the booted system.  Thus the system is 100mb  boot, small 100mb swap and the rest root of two 16GB CF cards.

I assume that I must refer to the added device as partition#2 since it is partitioned as root for the other drives.  I can try to --add it as just /dev/sde but don't expect it will change things.EDIT: no change occured.

Last edited by lilsirecho (2011-12-07 16:16:58)


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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#4 2011-12-07 18:37:23

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Try adding the device first:

[root@n6re ~]# mdadm --add /dev/md0 /dev/sde2

Use cat /proc/mdstat to track the progess, then once it's done and the device has been added then grow the array.

[root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3

I recently did this for a Raid6 storage array and it worked fine, though it took a while since I was adding 2 1Tb drives.


Edit:  Probably a silly question but you do have an /dev/sde2 partition right?  If you mirrored the partition structure on /dev/sde as you have on /dev/sda and /dev/sdb then you should be good to go.  If not you'll need to replace the --add /dev/sde2 with /dev/sde* (the * being whatever you have).

Last edited by imatechguy (2011-12-07 18:45:04)

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#5 2011-12-07 18:44:51

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

imatechguy:

The mdadm.conf makes specific reference to raid0 in --grow mode which stipulates that --grow and --add are needed in the same command.

The problem here seems to require a kernel mod to enable raid4 which is used to re-sync raid0 and then re-establish raid0.

This procedure worked before linux3 but no longer has kernel support.

What is required in the kernel to support this function is something I have no clue about.

That is my understanding of the problem at the moment.

EDIT:  Since the mdadm man page info does not produce the --grow it is possible that the capability is history and the mdadm man page needs upgrading.

Last edited by lilsirecho (2011-12-07 18:47:25)


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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#6 2011-12-07 18:55:29

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Ah, just now realizing you were trying to grow a Raid0 not a Raid4.  If I'm not mistaken mdadm doesn't support adding drives to Raid0 or Raid10 arrays, only replacing existing devices with larger capacity drives so I'm not certain it's a kernel thing.

Depending on size and your access to spare HDD's you could copy/move your existing array to a single drive, kill off md0 and recreate it with the three drives you have for it now.

Sorry about that I just mis-read the raid level you were using.

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#7 2011-12-07 20:53:32

kurych
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From: Saint-Petersburg, Russia
Registered: 2011-12-07
Posts: 27

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

imatechguy is right: impossible to grow raid0. You can look article, in chapter "Contrasting RAID-0 and LVM":

In the case of mdadm and software RAID-0 on Linux, you cannot grow a RAID-0 group. You can only grow a RAID-1, RAID-5, or RAID-6 array. This means that you can’t add drives to an existing RAID-0 group without having to rebuild the entire RAID group but having to restore all the data from a backup.

Therefore article was writen in 2009, I think, that behavior don't changed until now.

Last edited by kurych (2011-12-07 20:54:44)

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#8 2011-12-07 20:55:52

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Imatechguy:
The understanding I have is that I have done this --grow function in the past but not since linux 3.  So the problem is in the linux three setup somewhere.

Man mdadm allows for raid0 to grow as I descibed.


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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#9 2011-12-07 21:35:56

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

I'm not at home so I don't have access to a Linux machine so the closest I have to a man page is this:
http://linux.die.net/man/8/mdadm

Scrolling down the page a bit you can see this, which is probably what you are seeing in the .conf file.

Grow
Grow (or shrink) an array, or otherwise reshape it in some way. Currently supported growth options including changing the active size of component devices and changing the number of active devices in Linear and RAID levels 0/1/4/5/6, changing the RAID level between 0, 1, 5, and 6, and between 0 and 10, changing the chunk size and layout for RAID 0,4,5,6, as well as adding or removing a write-intent bitmap.

However if you scroll down a bit more you'll see this section:

For create, build, or grow:
-n, --raid-devices=

Specify the number of active devices in the array. This, plus the number of spare devices (see below) must equal the number of component-devices (including "missing" devices) that are listed on the command line for --create. Setting a value of 1 is probably a mistake and so requires that --force be specified first. A value of 1 will then be allowed for linear, multipath, RAID0 and RAID1. It is never allowed for RAID4, RAID5 or RAID6.
This number can only be changed using --grow for RAID1, RAID4, RAID5 and RAID6 arrays, and only on kernels which provide the necessary support.

I think mdadm has been that way for some time, no idea on how long but you can google and easily find related posts going back to 2008.  Is it possible you remember using the --grow option with a different Raid level or perhaps when replacing existing HDDs with larger capacity ones instead of adding additional devices?


Edit: Note emphasis in second quote is mine.

Last edited by imatechguy (2011-12-07 21:37:35)

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#10 2011-12-07 22:01:46

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

imatechguy:
Much in mdadm regards the non- raid0 setups.

Further down in mdadm man page there is a grow section which describes as I have reported.

My use of --grow using the procedure I have posted was to grow a two device cf raid0 array to an eventual 5 device cf card array running 306MB/sec hdparm.

This 5 device raid0 array was bootable and in kernel26v 39.

When I upgrade to linux 3 the raid arrayno longer functioned.  I have since restarted raid0 woth 2 devices using kernel26v39 as a starter.

Some linux3 versions allow the raid0 to boot, after modifying grub kernel line.

Most linux3 versions kill the boot and refuse to respond to uuid for booting.

One linux version 3.1.1-1 permits booting with added kernel data.

None 9of the linux kernels allow --grow as described in the man pages for mdadm.

I am informed that there is a mdadm_udev which doesn't appear anywhere in the man pages.

I have had success with this raid0 but not with --grow in raid0.

I hope some mdadm expert can explain what is necessary to enable --grow in raid0 format......with linux3 versions of the kernel(verified that it introduces the fail to boot and the fail to --grow.

It has been done and should still be possible.

(I have also been able to re-size the devices to produce a 29GB /dev/md0. 

I am anxious to produce a three device raid0 before I resize again.

So this post has presented the problem.............

EDIT:  I am 86 years young and would appreciate  a solution before I am 87

EDIT:  My system is x86_64 with 4GBram.

Last edited by lilsirecho (2011-12-08 03:02:25)


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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#11 2011-12-07 23:37:15

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Perhaops the linux3 kernels have a hangup with mdadm arrays and cannot recognize /dev/md0.

During boot-up, mdadm starts /dev/mdo as raid0 with 2 drives.

Very shortly thereafter the root device (/dev/md0) uuid fails to be found and ramfs is initiated.

This suggests that /dev/md0 is the problem and not raid4 initiation..

If there is no /dev/md0 then raid4 won't happen.So ls /dev....

h-4.2# ls dev
adsp		    parport0  tty17  tty52    vcs23  vcs59   vcsa36
agpgart		    port      tty18  tty53    vcs24  vcs6    vcsa37
audio		    ppp       tty19  tty54    vcs25  vcs60   vcsa38
autofs		    psaux     tty2   tty55    vcs26  vcs61   vcsa39
block		    ptmx      tty20  tty56    vcs27  vcs62   vcsa4
bsg		    pts       tty21  tty57    vcs28  vcs63   vcsa40
btrfs-control	    random    tty22  tty58    vcs29  vcs7    vcsa41
bus		    rtc       tty23  tty59    vcs3   vcs8    vcsa42
char		    rtc0      tty24  tty6     vcs30  vcs9    vcsa43
console		    sda       tty25  tty60    vcs31  vcsa    vcsa44
core		    sda1      tty26  tty61    vcs32  vcsa1   vcsa45
cpu		    sda2      tty27  tty62    vcs33  vcsa10  vcsa46
cpu_dma_latency     sdb       tty28  tty63    vcs34  vcsa11  vcsa47
disk		    sdb1      tty29  tty7     vcs35  vcsa12  vcsa48
dri		    sdb2      tty3   tty8     vcs36  vcsa13  vcsa49
dsp		    sdc       tty30  tty9     vcs37  vcsa14  vcsa5
fb0		    sdc1      tty31  ttyS0    vcs38  vcsa15  vcsa50
fd		    sdc2      tty32  ttyS1    vcs39  vcsa16  vcsa51
full		    sdd       tty33  ttyS2    vcs4   vcsa17  vcsa52
fuse		    sdd1      tty34  ttyS3    vcs40  vcsa18  vcsa53
hidraw0		    sdd2      tty35  uinput   vcs41  vcsa19  vcsa54
hidraw1		    sdd3      tty36  urandom  vcs42  vcsa2   vcsa55
hidraw2		    sdd4      tty37  usb      vcs43  vcsa20  vcsa56
hpet		    shm       tty38  vcs      vcs44  vcsa21  vcsa57
initctl		    snapshot  tty39  vcs1     vcs45  vcsa22  vcsa58
input		    snd       tty4   vcs10    vcs46  vcsa23  vcsa59
kmsg		    stderr    tty40  vcs11    vcs47  vcsa24  vcsa6
log		    stdin     tty41  vcs12    vcs48  vcsa25  vcsa60
loop0		    stdout    tty42  vcs13    vcs49  vcsa26  vcsa61
mapper		    tty       tty43  vcs14    vcs5   vcsa27  vcsa62
mcelog		    tty0      tty44  vcs15    vcs50  vcsa28  vcsa63
md		    tty1      tty45  vcs16    vcs51  vcsa29  vcsa7
md0		    tty10     tty46  vcs17    vcs52  vcsa3   vcsa8
mem		    tty11     tty47  vcs18    vcs53  vcsa30  vcsa9
mixer		    tty12     tty48  vcs19    vcs54  vcsa31  vga_arbiter
net		    tty13     tty49  vcs2     vcs55  vcsa32  watchdog
network_latency     tty14     tty5   vcs20    vcs56  vcsa33  zero
network_throughput  tty15     tty50  vcs21    vcs57  vcsa34
null		    tty16     tty51  vcs22    vcs58  vcsa35
sh-4.2# 

So /dev/md0 is recognized?  But not by some other process?

Gparted does not list /dev/md0 when booted in raid0

sh-4.2# gparted
======================
libparted : 3.0
======================
Could not stat device /dev/md/0 - No such file or directory.

As reported, gparted shows /dev/md0 as /dev/md/0..  This indicates some ID variance within the kernel which I cannot explain.

sh-4.2# mount /dev/md0 /mnt/md
sh-4.2# 

This command mounts /dev/md0 in /mnt/md....

sh-4.2# mount /dev/md0 /mnt/md
sh-4.2# 

Thus:

sh-4.2# ls
bin   etc       kdenlive  lib64     mnt   root  srv  usr
boot  home       lib         lost+found  opt   run   sys  var
dev   jumanji-git  lib32     media     proc  sbin  tmp
sh-4.2#
That is the full archlinux listing and it is obtained from /dev/md0.

Why the discrepant ID in gparted?

Perhaps mdadm has been upgraded, which means the same in linux land as it does in windows...your package is "improved" such that it fails........

One note which is pertinent....this raid0 has been upgraded yesterday without linux kernel install.

Thus, all upgrades have occured except the kernel.

I have another pair of CF cards also upgraded without linux initially,,,and then linux 3.1.1-1 was added with pacman-U.  This linux build can boot with kernel line entries but it does not allow --grow /dev/md0 either.  In fact, it boots with ...root=/dev/md0 in the kernel line.

Without that in the kernel line, it fails to find the uuid for /dev/md0,,,,even though it was started with mdadm just prior to that failure.

Cannot --grow /dev/md0 if it isn't recognized!!!!!!!

UUID is supposed to solve all problems in boot!!!!He He.........

Edit: From  2.6.35, the Linux Kernel is able to convert a RAID0 in to a RAID4
       or RAID5.  mdadm uses this functionality and the ability to add devices
       to  a RAID4 to allow devices to be added to a RAID0.  When requested to
       do this, mdadm will convert the RAID0 to a  RAID4,  add  the  necessary
       disks  and  make the reshape happen, and then convert the RAID4 back to
       RAID0.

This doesn't happen!!!!!!!

Last edited by lilsirecho (2011-12-08 00:27:28)


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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#12 2011-12-09 05:01:59

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

I finally got a chance to read the mdadm man page at home and did indeed find the following after scrolling way down to the "RAID-DEVICES CHANGES" subsection under "GROW MODE".

From 2.6.35, the Linux Kernel is able to convert a RAID0 in to a RAID4 or RAID5.  mdadm uses this functionality
       and  the ability to add devices to a RAID4 to allow devices to be added to a RAID0.  When requested to do this,
       mdadm will convert the RAID0 to a RAID4, add the necessary disks and make the reshape happen, and then  convert
       the RAID4 back to RAID0.

According to that it should technically be possible to use the --grow option to add devices to a Raid0 array, though to be honest I've never before heard anyone say it could be done.  So going back to your original command I notice you didn't tell mdadm which array to add the /dev/sde2 device to; but also try putting the add option before the grow option like so:

# mdadm --add /dev/md0 /dev/sde2 --grow /dev/md0 --raid-devices=3 

If that doesn't work I'd reiterate the conventional understanding being that it's not possible to add devices to a Raid0 array with mdadm, but perhaps filing a bug report will get the right peoples attention for a fix or at least the documentation updated to accurately reflect available functionality.  Either way good luck I hope you get it sorted out.

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#13 2011-12-09 14:18:41

lilsirecho
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Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

There are several options to utilize in mdadm for raid arrays.  These are prefaced in commands to perform changes in raid arrays.  One of these is --grow.  There is no preface named --add so that cannot be the first option.  Therefore the arrangement you present is not an option.

This does seem like an item to report as a bug since it did function and was outlined in mdadm as such in previous kernel releases and I have utilized it many times.

I appreciate your comments.

Most of the googled data on the subject is completely old and based on  adding a patch to mdadm in the year 2009.

I will try to obtain help via a bug.


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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#14 2011-12-09 14:57:43

lilsirecho
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Posts: 5,000

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Entered flyspray bug with FS#27507.........................


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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#15 2011-12-09 15:16:09

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

lilsirecho wrote:

There is no preface named --add so that cannot be the first option.  Therefore the arrangement you present is not an option.

I'll repectfully disagree with that statement.  It may or may not work in your situation but if you don't try it you won't know whether or not it works.  Give the below links a read as well as the man page and you'll several references to "--add".  Also depending on whether or not you are adding device or recovering from a failed device there are other references to 

 # mdadm --manage --add <array> <device>

Might as well try both options.


http://en.wikipedia.org/wiki/Mdadm


https://wiki.archlinux.org/index.php/RAID

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#16 2011-12-09 16:13:35

lilsirecho
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Posts: 5,000

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

The function that you specified gives the error that -add cannot be used as the mode, --grow is required.

I have tried all possible modes for a solution...all give errors...the finction and command I listed is the only command that can perform the ==grow of a raid0 array ...if the kernel allows!!!!

The man mdadm pages state it is kernel related by implication...therefore I generated a bug...perhaps not the correct thing to do but it may result in some action.

A kernel request might be better?

I appreciate your interest in my dilemma and assure you I have investigated it thoroughly.  Because it is a special case involving the dreaded raid0 (I love it) it isn't well-documented nor is it well-understood.

My system runs at flank speed booting in ten seconds and has been functioning nicely for months.  I desire to --grow and to re-size eventually but --grow is first to establish the performance available in three CF cards for comparison with other raid methods.

I have 4GB ram so don't use swap even though I have 100mb assigned in one partition.  I don't play games either.  Just have boot and root and it flies.

I note that one mdadm patch for the raid0 problem was generated in 2009, therefore, it can be done with kernel support.  What exactly is required therein is not in my purview.

Thanks for your interest.

EDIT:  Example of error statements:

sh-4.2# mdadm --grow /dev/md0 --add /dev/sdc2
mdadm: can only add devices to linear arrays
sh-4.2# 
sh-4.2# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sdc2
mdadm: /dev/md0: could not set level to raid4
sh-4.2# 

 
As the error implies, mdadm uses raid4 to re-sync raid0 but cannot setup raid4 because the kernel hasn't the means to do so.

EDIT:  I am posting while booted in raid0.............................................................

Last edited by lilsirecho (2011-12-09 16:45:56)


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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#17 2011-12-09 17:55:24

imatechguy
Arch Linux f@h Team Member
Registered: 2010-03-22
Posts: 66

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Okay last idea here, did you run modprobe for raid4 before trying to add the device and grow the array?  You've obviously got raid0 going or you wouldn't be able to run it but since mdadm uses raid4 to grow a raid0 I was wondering if you have that?  Probably no need to add it to your rc.conf since you should only need it long enough for the array to grow.

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#18 2011-12-09 19:10:59

lilsirecho
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Posts: 5,000

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

All references to --grow in ggogling report that modprobe does not cut it...it must be built into the kernel(or patched).

When using....cat /proc/mdstat while booted into arch from hdd, the personalities include raid0 raid 4 raid 5 and raid6.  It is in this arena that I try to --grow raid0.

Since the personalities are correct, the kernel has those elements installed and no modprobe is required.....additionally, it seems it must be included in kernel boot-up rather than modprobe.

This makes sense since the re-sync is a major operation requiring many kernel functions and it must ne built in(according to all references in googling).

This kernel data is provided for many raid modes that are more safely used in linux but raid0 is not projected as desireable.  This would be true for users whose activities require many, many writes when using ssds or CF cards.  It is risky with hdd's if one fails the raid0 is lost.

I do not expect to lose a CF raid0 for years and do have backups.  The disposition of data in a CF cards is not identical to that provided in hdd's and writes don't occur in the same cells over and over.

The kernel needs to be modded to allow the --grow function as described in mdadm m,an pages.

EDIT:  Be aware that this raid0 is even more complex than a grow option.  The raid0 bootable that I run is partitioned as well and setting up a partitioned boot is not probable in the new linux3 .

Last edited by lilsirecho (2011-12-09 21:51:01)


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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#19 2011-12-09 21:54:58

lilsirecho
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Posts: 5,000

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Main purpose to --grow is to provide more new cells to write to and thereby extend the life of the Compact Flash devices since algorithms internal to the devices control the writes, eliminating bad cells and writing to new cells.

Thus it isn't speed that is needed but capacity!


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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#20 2011-12-10 00:12:21

lilsirecho
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Registered: 2003-10-24
Posts: 5,000

Re: [root@n6re ~]# mdadm --grow /dev/md0 --raid-devices=3 --add /dev/sde2

Added info:

sh-4.2# lsinitcpio -a /boot/initramfs-linux.img
==> Image: /boot/initramfs-linux.img
==> Kernel: 3.1.1-1-ARCH
==> Compressed with: gzip
  -> Compression ratio: .553
  -> Estimated decompression time: 0.096s

==> Included modules:
  ata_piix [explicit]	  hid-magicmouse	  hid-uclogic
  ehci-hcd [explicit]	  hid-microsoft		  hid-wacom
  ext2 [explicit]	  hid-monterey		  hid-waltop
  ext3 [explicit]	  hid-multitouch	  hid-wiimote
  fb_sys_fops		  hid-ntrig		  hid-zpff
  ff-memless		  hid-ortek		  hid-zydacron
  hid			  hid-petalynx		  jbd
  hid-a4tech		  hid-picolcd		  lcd
  hid-apple		  hid-pl		  libata
  hid-axff		  hid-prodikeys		  mbcache
  hid-belkin		  hid-quanta		  md-mod
  hid-cherry		  hid-roccat		  pata_acpi
  hid-chicony		  hid-roccat-arvo	  raid0
  hid-cypress		  hid-roccat-common	  scsi_mod
  hid-dr		  hid-roccat-kone	  sd_mod
  hid-elecom		  hid-roccat-koneplus	  snd
  hid-emsff		  hid-roccat-kovaplus	  snd-rawmidi
  hid-ezkey		  hid-roccat-pyra	  snd-seq-device
  hid-gaff		  hid-samsung		  soundcore
  hid-gyration		  hid-sjoy		  syscopyarea
  hid-holtekff		  hid-sony		  sysfillrect
  hid-kensington	  hid-speedlink		  sysimgblt
  hid-keytouch		  hid-sunplus		  uhci-hcd [explicit]
  hid-kye		  hid-tmff		  usbcore
  hid-lcpower		  hid-topseed		  usbhid
  hid-logitech		  hid-twinhan

==> Included binaries:
  /sbin/switch_root
  /sbin/udevadm
  /sbin/modprobe
  /sbin/blkid
  /sbin/mdassemble
  /bin/mount
  /bin/busybox

==> Hook run order:
  udev
  mdadm

sh-4.2# 

This is the list when booted into raid0 as I am now.


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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