Should it be possible to hot-swap SATA drives with Centos5? It doesn't seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices change names and keeps grub from finding /boot on a scsi drive that is shifted up.
On 8/21/07, Les Mikesell lesmikesell@gmail.com wrote:
Should it be possible to hot-swap SATA drives with Centos5? It doesn't seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices change names and keeps grub from finding /boot on a scsi drive that is shifted up.
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
Which controllers allow it?
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-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Jim Perrin Sent: Tuesday, August 21, 2007 14:13 To: CentOS mailing list Subject: Re: [CentOS] Hot swap SATA?
On 8/21/07, Les Mikesell lesmikesell@gmail.com wrote:
Should it be possible to hot-swap SATA drives with Centos5?
It doesn't
seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices
change names
and keeps grub from finding /boot on a scsi drive that is
shifted up.
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
-- During times of universal deceit, telling the truth becomes a revolutionary act. George Orwell _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
On 8/21/07, Jason Pyeron jpyeron@pdinc.us wrote:
Which controllers allow it?
Well, I don't happen to have a comprehensive list handy, but Serveraid 8x series cards in our x3650 and x3850's support this.
I believe 3ware also has some products that support hotswap.
The backplane and controller card have to support such operations.
Jim Perrin wrote:
Should it be possible to hot-swap SATA drives with Centos5? It doesn't seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices change names and keeps grub from finding /boot on a scsi drive that is shifted up.
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
How are the names supposed to work when one may be missing at bootup and added later?
On 8/21/07, Les Mikesell lesmikesell@gmail.com wrote:
Jim Perrin wrote:
How are the names supposed to work when one may be missing at bootup and added later?
In theory, this should be handled with LABEL=foo, instead of using /dev/sdxY, however all the cards I've seen allowing hotswap are raid cards. The system sees just one drive, from the raid controller, and you'd better still have enough drives to support the raid array.
Les Mikesell wrote:
Jim Perrin wrote:
Should it be possible to hot-swap SATA drives with Centos5? It doesn't seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices change names and keeps grub from finding /boot on a scsi drive that is shifted up.
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
How are the names supposed to work when one may be missing at bootup and added later?
I thought the system would just assign the next available /dev/sdx?
Then there was the post about wanting to be able to pull a SATA/eSATA disk in and have the system automatically mount whatever filesystem is on the disk...
On OpenSolaris, SATA hotswapping and device naming is a complete non-issue.
On Tuesday 21 August 2007, Feizhou wrote:
Les Mikesell wrote:
Jim Perrin wrote:
Should it be possible to hot-swap SATA drives with Centos5?
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
How are the names supposed to work when one may be missing at bootup and added later?
I thought the system would just assign the next available /dev/sdx?
Then there was the post about wanting to be able to pull a SATA/eSATA disk in and have the system automatically mount whatever filesystem is on the disk...
That was mine. Still working on it.
As to the hardware support, the definitive answer is found at www.linux-ata.org
As to device naming, use LABEL= to fix that. SCSI device naming on Linux stinks.
I'm dinking around with a Ubuntu install right now that is giving me fits because of linux PCI/SCSI weirdness. The boot drive (as set in the BIOS) is probed by the kernel as /dev/sdc. Fun. The setup has two 80GB drives in MD RAID1 (200MB /boot on /dev/md0, and 77GB / on /dev/md1, both on the same drives) and four 250GB drives in 3-disk RAID5 with a hotspare. The drives are spread on three two port controllers (no, I don't have a four or six port controller handy, not an option in this case). Still working grub to get the thing to boot....
LABEL= does actually have its uses; I migrated a filesystem on a CentOS 4 VM running on one of our two VMware ESX beasts (2x Dell 6950, 4x dual core Opterons, 32GB RAM each, dual 4Gb/s fibre-channel to 2x EMC CLARiiON CX3-10c's with 20TB each) from the internal 3x300GB RAID to a 1.95TB LUN on the CX3. By using LABEL=, I was able to blow the drive away in VI Client on the VM, and boot right up without device ordering problems.
But I have also been bitten by the 'LABELs are the same on cloned disks' fun and games....
What I'm currently doing with the eSATA deal is having an entry in fstab, set to noauto, and using LABEL=, and an icon in KDE to mount it on the desktop. it is not seamless; unmounting is much more of a chore, as KDE has fun with the icon, doesn't enable the context menu 'safely remove' (aka, unmount) option, etc. But it's better than nothing. Just haven't had time to see how to enable SCSI removable support (dig through the udev and hotplug stuff sometime and you'll see what I mean) in libata as yet. With SCSI removable support (which usbstorage implements, which is why it works) the system Just Works properly.
Lamar Owen wrote:
On Tuesday 21 August 2007, Feizhou wrote:
Les Mikesell wrote:
Jim Perrin wrote:
Should it be possible to hot-swap SATA drives with Centos5?
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
How are the names supposed to work when one may be missing at bootup and added later?
I thought the system would just assign the next available /dev/sdx?
Then there was the post about wanting to be able to pull a SATA/eSATA disk in and have the system automatically mount whatever filesystem is on the disk...
That was mine. Still working on it.
Would it have to smarts to live partition type FD alone?
As to the hardware support, the definitive answer is found at www.linux-ata.org
As to device naming, use LABEL= to fix that. SCSI device naming on Linux stinks.
Oh yeah!
I'm dinking around with a Ubuntu install right now that is giving me fits because of linux PCI/SCSI weirdness. The boot drive (as set in the BIOS) is probed by the kernel as /dev/sdc. Fun. The setup has two 80GB drives in MD RAID1 (200MB /boot on /dev/md0, and 77GB / on /dev/md1, both on the same drives) and four 250GB drives in 3-disk RAID5 with a hotspare. The drives are spread on three two port controllers (no, I don't have a four or six port controller handy, not an option in this case). Still working grub to get the thing to boot....
Ugh...
LABEL= does actually have its uses; I migrated a filesystem on a CentOS 4 VM running on one of our two VMware ESX beasts (2x Dell 6950, 4x dual core Opterons, 32GB RAM each, dual 4Gb/s fibre-channel to 2x EMC CLARiiON CX3-10c's with 20TB each) from the internal 3x300GB RAID to a 1.95TB LUN on the CX3. By using LABEL=, I was able to blow the drive away in VI Client on the VM, and boot right up without device ordering problems.
:-)
But I have also been bitten by the 'LABELs are the same on cloned disks' fun and games....
What I'm currently doing with the eSATA deal is having an entry in fstab, set to noauto, and using LABEL=, and an icon in KDE to mount it on the desktop. it is not seamless; unmounting is much more of a chore, as KDE has fun with the icon, doesn't enable the context menu 'safely remove' (aka, unmount) option, etc. But it's better than nothing. Just haven't had time to see how to enable SCSI removable support (dig through the udev and hotplug stuff sometime and you'll see what I mean) in libata as yet. With SCSI removable support (which usbstorage implements, which is why it works) the system Just Works properly.
Maybe when I get a box to play with....the OpenSolaris box is already in production so I cannot experiment there.
Lamar Owen wrote:
Should it be possible to hot-swap SATA drives with Centos5?
Depends on the SATA controller, but yes. If the controller allows, you can hotswap sata drives.
How are the names supposed to work when one may be missing at bootup and added later?
I thought the system would just assign the next available /dev/sdx?
Then there was the post about wanting to be able to pull a SATA/eSATA disk in and have the system automatically mount whatever filesystem is on the disk...
That was mine. Still working on it.
As to the hardware support, the definitive answer is found at www.linux-ata.org
Thanks - the problem must be the Promise controller. I'll have to dig up something else.
As to device naming, use LABEL= to fix that. SCSI device naming on Linux stinks.
Can grub deal with that for the /boot partition? A default install on a scsi drive that came in after the sata's wouldn't boot if I removed one of the sata disks.
What I want to end up with is the system on a pair of raid 1 scsi drives, then a 3-member raid1 mounted separately where one is periodically swapped out and taken offsite. I'm currently doing something similar with 2 IDE and one firewire drive but the firewire driver doesn't seem reliable enough to leave the drive connected much longer than it takes to sync.
As to device naming, use LABEL= to fix that. SCSI device naming on Linux stinks.
Quick question regarding the naming issue (and sorry for hijacking this thread). My CentOS 4.5 desktop system has two SATA drives: the boot drive is /dev/hda1 and the second drive is /dev/sda1. Is this the expected naming convention? It really got me confused and this was partly the reason why I accidentally initialized my boot partition recently while trying to add the second drive.
Alfred
From: Alfred von Campe
As to device naming, use LABEL= to fix that. SCSI device naming on Linux stinks.
Quick question regarding the naming issue (and sorry for hijacking this thread). My CentOS 4.5 desktop system has two SATA drives: the boot drive is /dev/hda1 and the second drive is /dev/sda1.
/dev/hda is being controlled by a controller that mimics an IDE drive and is being accessed through the kernel's ide layer. /dev/sda is being controlled by a libata-supported controller and is being accessed through the kernel's scsi stack with libata.
All IDE and ATA drives under later kernels will be libata supported, and will show up as /dev/sdx drives. -- Lamar Owen Chief Information Officer Pisgah Astronomical Research Institute 1 PARI Drive Rosman, NC 28772 828-862-5554 www.pari.edu
Alfred
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/dev/hda is being controlled by a controller that mimics an IDE drive and is being accessed through the kernel's ide layer. /dev/ sda is being controlled by a libata-supported controller and is being accessed through the kernel's scsi stack with libata.
As far as I know, all drives (2 hard disks and 2 optical drives) are on the same controller. Well, all 4 are plugged in to the motherboard of a Lenovo ThinkCentre M55 PC. There is no separate controller, unless there is more than one on the motherboard itself. In the BIOS, these drives all appeared together numbered 1-5 (with one of these missing because there are only 4 devices total).
Alfred
On Wednesday 22 August 2007, Alfred von Campe wrote:
As far as I know, all drives (2 hard disks and 2 optical drives) are on the same controller. Well, all 4 are plugged in to the motherboard of a Lenovo ThinkCentre M55 PC. There is no separate controller, unless there is more than one on the motherboard itself.
Many motherboards that have more than two SATA connectors put two on the SouthBridge's IDE-type controller, and the others on 'something else'. Usually, the 'something else' shows as a SCSI controller in Linux. How many SATA connectors are there?
I have seen a few motherboards use the Intel ICH ports as the first two, then put either a Promise or SiliconImage controller on the board to handle the other two or four ports (typically labeled as being 'RAID' ports). The ICH will show as /dev/hdx, and the SiI or Promise will show as /dev/sdx.
On Aug 23, 2007, at 9:08, Lamar Owen wrote:
Many motherboards that have more than two SATA connectors put two on the SouthBridge's IDE-type controller, and the others on 'something else'. Usually, the 'something else' shows as a SCSI controller in Linux. How many SATA connectors are there?
The User guide says they are 5 connectors, but I can only see 4. Three of them are very close to each other, and the fourth one is a little further away. Wouldn't you know it, my boot drive is connected to the one that is by itself. Maybe if it had been connected to one of the other three, it would have been /dev/sda (or / dev/sdb).
Like I mentioned in my previous post, I have two hard disks and two optical drives. Here are the device names:
# ls -l /dev/[cdhs][vd]* lrwxrwxrwx 1 root root 3 Aug 20 12:24 /dev/cdrom -> hdc lrwxrwxrwx 1 root root 4 Aug 20 12:24 /dev/cdrom1 -> scd0 lrwxrwxrwx 1 root root 4 Aug 20 12:24 /dev/cdwriter -> scd0 lrwxrwxrwx 1 root root 3 Aug 20 12:24 /dev/dvd -> hdc lrwxrwxrwx 1 root root 4 Aug 20 12:24 /dev/dvd1 -> scd0 lrwxrwxrwx 1 root root 4 Aug 20 12:24 /dev/dvdwriter -> scd0 brw-rw---- 1 root disk 3, 0 Aug 20 12:23 /dev/hda brw-rw---- 1 root disk 3, 1 Aug 20 12:23 /dev/hda1 brw-rw---- 1 root disk 3, 2 Aug 20 12:23 /dev/hda2 brw------- 1 root disk 22, 0 Aug 20 12:23 /dev/hdc brw-rw---- 1 root disk 8, 0 Aug 20 12:23 /dev/sda brw-rw---- 1 root disk 8, 1 Aug 20 12:23 /dev/sda1
It is strange indeed.
Alfred
On Thursday 23 August 2007, Alfred von Campe wrote:
The User guide says they are 5 connectors, but I can only see 4. Three of them are very close to each other, and the fourth one is a little further away. Wouldn't you know it, my boot drive is connected to the one that is by itself. Maybe if it had been connected to one of the other three, it would have been /dev/sda (or / dev/sdb).
Ok, run a 'lspci' and see if it lists two controllers.
Ok, run a 'lspci' and see if it lists two controllers.
Yup, it does:
# lspci | fgrep IDE 00:1f.2 IDE interface: Intel Corporation 82801H (ICH8 Family) 4 port SATA IDE Controller (rev 02) 00:1f.5 IDE interface: Intel Corporation 82801H (ICH8 Family) 2 port SATA IDE Controller (rev 02)
That definitely settles it. We now return you to your regularly scheduled topic...
Thanks, Alfred
Just to add my 5 cents (centos 5 cents that is har har)...
I have several plain jane seagate sata drives, connected mostly to nforce4 sata (module sata_nv) controller, and a few connected to a silicon image controller (sata_sil) ... hot swap is a non issue for me. All my drives are part of MD raid sets - I down the drive using mdadm, and then just pull it from the chassis (Supermicro 5 drive chassis). Adding a new drive is equally easy, just slide it into the chassis and use mdadm to add it to an array.
Gordon
On 8/21/07, Les Mikesell lesmikesell@gmail.com wrote:
Should it be possible to hot-swap SATA drives with Centos5? It doesn't seem to work on my system. Removing an unmounted drive locked the system up, and leaving one out at bootup makes the devices change names and keeps grub from finding /boot on a scsi drive that is shifted up.
-- Les Mikesell lesmikesell@gmail.com _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
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Les Mikesell