do you have the udev configuration for this (static)?
2011/2/24 Iordan Iordanov <iordan@xxxxxxxxxxxxxxx>:
> Hi guys,
>
> I saw a bunch of discussion of devices changing names when hot-plugged. If
> you get the device name right when you add it to the array first, all is
> good since the superblock is used to "discover" the device later.
>
> However, to make things easier/clearer, and to avoid errors, one can take a
> look at the set of directories:
>
> /dev/disk/by-id
> /dev/disk/by-path
> /dev/disk/by-uuid
> /dev/disk/by-label
>
> for a predictable, more static view of the drives. The symlinks in these
> directories are created by udev, and are simply links to the "real" device
> nodes /dev/sd{a-z}*. You can either just use these symlinks as a way of
> verifying that you are adding the right device, or add the device using the
> symlink.
>
> At our location, we even augmented udev to add links to labeled GPT
> partitions in /dev/disk/by-label, and now our drives/partitions look like
> this:
>
> iscsi00-drive00-part00 -> ../../sda1
> iscsi00-drive01-part00 -> ../../sdb1
> iscsi00-drive02-part00 -> ../../sdc1
> iscsi00-drive03-part00 -> ../../sdd1
> iscsi00-drive04-part00 -> ../../sde1
>
> This way, we know exactly which bay contains exactly which drive, and it
> stays this way. If you guys want, I can share with you the changes to udev
> necessary and the script which extracts the GPT label and reports it to udev
> for this magic to happen :). Please reply to this thread with a request if
> you think it may be useful to you.
>
> Cheers,
> Iordan
>
>
> On 02/23/11 17:13, Roberto Nunnari wrote:
>>
>> Roberto Spadim wrote:
>>>
>>> hum, maybe you are using mdadm.conf or autodetect, non autodetect
>>> should be something like this:
>>> i donÂt know the best solution, but it works ehhehe
>>>
>>> kernel /vmlinuz-2.6.9-89.31.1.ELsmp ro root=/dev/md0 rhgb
>>> quiet md=0,/dev/sda,/dev/sdb md=1,xxxx,yyyy.....
>>>
>>> or another md array...
>>>
>>> humm i readed the sata specification and removing isnÂt a problem, at
>>> eletronic level the sata channel is only data, no power source, all
>>> channels are diferencial (like rs422 or rs485), i donÂt see anyproblem
>>> removing it. i tryed hot plug a revodrive (pciexpress ssd) and it
>>> donÂt work (reboot) hehehe, pci-express isnÂt hot plug =P, sata2 donÂt
>>> have problems, the main problem is a short circuit at power source, if
>>> you remove with caution no problems =)
>>>
>>> i tried in some others distros and udev created a new device when add
>>> a diferent disk for example, remove sdb, and add another disk create
>>> sdc (not sdb), maybe with another udev configuration should work
>>
>> Ok. I'll keep all that in mind tomorrow.
>> Best regards.
>> Robi
>>
>>
>>>
>>>
>>> 2011/2/23 Roberto Nunnari <roberto.nunnari@xxxxxxxx>:
>>>>
>>>> Roberto Spadim wrote:
>>>>>
>>>>> i donÂt know how you setup your kernel (with or without raid
>>>>
>>>> I use the official CentOS kernel with no modification and don't
>>>> know about raid autodetect, but:
>>>> # cat /boot/config-2.6.24-28-server |grep -i raid
>>>> CONFIG_BLK_DEV_3W_XXXX_RAID=m
>>>> CONFIG_MD_RAID0=m
>>>> CONFIG_MD_RAID1=m
>>>> CONFIG_MD_RAID10=m
>>>> CONFIG_MD_RAID456=m
>>>> CONFIG_MD_RAID5_RESHAPE=y
>>>> CONFIG_MEGARAID_LEGACY=m
>>>> CONFIG_MEGARAID_MAILBOX=m
>>>> CONFIG_MEGARAID_MM=m
>>>> CONFIG_MEGARAID_NEWGEN=y
>>>> CONFIG_MEGARAID_SAS=m
>>>> CONFIG_RAID_ATTRS=m
>>>> CONFIG_SCSI_AACRAID=m
>>>>
>>>>
>>>>> autodetect?) do you use kernel command line to setup raid? autodetect?
>>>>
>>>> /dev/md0 in grub
>>>> I don't know if that means autodetect, but I guess so..
>>>>
>>>>
>>>>> here in my test machine iÂm using kernel command line (grub), i donÂt
>>>>> have a server with hotplug bay, i open the case and remove the wire
>>>>> with my hands =) after reconecting it with another device kerenel
>>>>
>>>> Is it safe? Isn't it a blind bet to fry up the controller and/or disk?
>>>>
>>>>
>>>>> recognize the new device reread the parititions etc etc and i can add
>>>>> it to array again
>>>>> my grub is something like:
>>>>>
>>>>> md=0,/dev/sda,/dev/sdb .....
>>>>>
>>>>> internal meta data, raid1, i didnÂt like the autodetect (itÂs good)
>>>>> but i prefer hardcoded kernel command line (itÂs not good with usb
>>>>> devices)
>>>>
>>>> the relevant part of my grub is:
>>>>
>>>> default=0
>>>> timeout=5
>>>> splashimage=(hd0,0)/grub/splash.xpm.gz
>>>> hiddenmenu
>>>> title CentOS (2.6.9-89.31.1.ELsmp)
>>>> root (hd0,0)
>>>> kernel /vmlinuz-2.6.9-89.31.1.ELsmp ro root=/dev/md0 rhgb quiet
>>>> initrd /initrd-2.6.9-89.31.1.ELsmp.img
>>>>
>>>> Best regards.
>>>> Robi
>>>>
>>>>
>>>>> 2011/2/23 Roberto Nunnari <roberto.nunnari@xxxxxxxx>:
>>>>>>
>>>>>> Roberto Spadim wrote:
>>>>>>>
>>>>>>> sata2 without hot plug?
>>>>>>
>>>>>> Hi Roberto.
>>>>>>
>>>>>> I mean that there is no hot-plug bay, with sliding rails etc..
>>>>>> The drives are connected to the mb using standard sata cables.
>>>>>>
>>>>>>
>>>>>>> check if your sda sdb sdc will change after removing it, itæ depends
>>>>>>> on your udev or another /dev filesystem
>>>>>>
>>>>>> Ok, thank you.
>>>>>> That means that if I take care to check the above, and
>>>>>> the new drive will be sdb, then taking the steps indicated
>>>>>> in my original post will do the job?
>>>>>>
>>>>>> Best regards.
>>>>>> Robi
>>>>>>
>>>>>>
>>>>>>> 2011/2/23 Roberto Nunnari <roberto.nunnari@xxxxxxxx>:
>>>>>>>>
>>>>>>>> Hello.
>>>>>>>>
>>>>>>>> I have a linux box, with two 2TB sata HD in raid 1.
>>>>>>>>
>>>>>>>> Now, one disk is in failed state and it has no spares:
>>>>>>>> # cat /proc/mdstat
>>>>>>>> Personalities : [raid1]
>>>>>>>> md1 : active raid1 sdb4[2](F) sda4[0]
>>>>>>>> 1910200704 blocks [2/1] [U_]
>>>>>>>>
>>>>>>>> md0 : active raid1 sdb1[1] sda2[0]
>>>>>>>> 40957568 blocks [2/2] [UU]
>>>>>>>>
>>>>>>>> unused devices: <none>
>>>>>>>>
>>>>>>>>
>>>>>>>> The drives are not hot-plug, so I need to shutdown the box.
>>>>>>>>
>>>>>>>> My plan is to:
>>>>>>>> # sfdisk -d /dev/sdb > sdb.sfdisk
>>>>>>>> # mdadm /dev/md1 -r /dev/sdb4
>>>>>>>> # mdadm /dev/md0 -r /dev/sdb1
>>>>>>>> # shutdown -h now
>>>>>>>>
>>>>>>>> replace the disk and boot (it should come back up, even without one
>>>>>>>> drive,
>>>>>>>> right?)
>>>>>>>>
>>>>>>>> # sfdisk /dev/sdb < sdb.sfdisk
>>>>>>>> # mdadm /dev/md1 -a /dev/sdb4
>>>>>>>> # mdadm /dev/md0 -a /dev/sdb1
>>>>>>>>
>>>>>>>> and the drives should start to resync, right?
>>>>>>>>
>>>>>>>> This is my first time I do such a thing, so please, correct me
>>>>>>>> if the above is not correct, or is not a best practice for
>>>>>>>> my configuration.
>>>>>>>>
>>>>>>>> My last backup of md1 is of mid november, so I need to be
>>>>>>>> pretty sure I will not lose my data (over 1TB).
>>>>>>>>
>>>>>>>> A bit abount my environment:
>>>>>>>> # mdadm --version
>>>>>>>> mdadm - v1.12.0 - 14 June 2005
>>>>>>>> # cat /etc/redhat-release
>>>>>>>> CentOS release 4.8 (Final)
>>>>>>>> # uname -rms
>>>>>>>> Linux 2.6.9-89.31.1.ELsmp i686
>>>>>>>>
>>>>>>>> Thank you very much and best regards.
>>>>>>>> Robi
>>
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--
Roberto Spadim
Spadim Technology / SPAEmpresarial
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