SATA hotswap / hotplug

[Christopher Mocock]

Hi list,

I'm trying to get SATA hot-swapping to work in Fedora 9 but I'm either 
having no luck or doing it wrong.

I've tried a variety of disk controllers including an LSI MegaRaid, 
3Ware 9550SX, and I'm now working with a Supermicro SAT2-MV8 (Marvell 
chipset - sata_mv module).

I was under the (possibly mistaken) impression that if I insert or 
remove a disk, I should see something in /var/log/messages. I've also 
been running "ls -l /dev/disk/by-path" to see if the device name appears 
or disappears, but it never does.

Is there any kind of special setup required or should it "just work"?

The disks I'm using are either Seagate SATA2 or older Hitachi SATA1 
drives, I have a few to play with. The disks are not formatted in any 
way as my application treats them as raw block devices. Still, I would 
expect to see the contents of /dev/disk/by-path to change when I insert 
or remove a disk.

When using the 3Ware card, I did get a message from the 3Ware driver 
saying that a disk had been removed or inserted, but it didn't change 
the contents of /dev/disk/by-path and the message was from the driver, 
not the kernel or udev or any other subsystem.

I should mention that the disks appear fine if they are inserted before 
I boot on all the disk controllers I've tried.

Any suggestions gratefully received.

Regards,

-- 
Chris

[Markku Kolkka]

Christopher Mocock kirjoitti viestissään (lähetysaika torstai, 
17. heinäkuuta 2008):
>  Well spotted, I saw this bit of the same page...
>
>  http://linux-ata.org/driver-status.html#marvell
>
>  ... and it says:
>
>  Driver name: sata_mv
>
>  Summary: Similar to ServerWorks "frodo": per-device queues,
>  full SATA control including hotplug.
>
>  So I'm a little bit puzzled. Unless it means hotplugging the
>  card itself?!? 
It means that the controller _hardware_ has the necessary 
features for hotplug support. The driver/feature matrix shows 
that the current version of sata_mv driver doesn't support 
hotplugging (but it may be added in future).

-- 
 Markku Kolkka
 markku.kolkka(a)iki.fi

[Seann Clark]

Christopher Mocock wrote:
>  Todd Denniston wrote:
> > lsi does not show up on http://linux-ata.org/driver-status.html so 
> > you have to figure out what driver supports the card and ask about 
> > that driver.
>
>  It's the megaraid_sas driver but it's not shown on the linux-ata.org 
>  site, so that doesn't bode too well!
>
> >> 3Ware 9550SX, 
> > http://linux-ata.org/driver-status.html#tware
> > apparently you need to ask at the driver maker's site if they support 
> > it.
>
>  Aha, I shall do so. 
Just as a quick heads up, with the 3ware cards, you have to
have JBOD 
support on, and a hotswap compliant enclosure for this. If you are using 
any type of RAID (I use RAID 5 on the three I have) it shows as one, 
maybe two drives (sda/b) in Linux though I have between 4-12 drives in 
the system. I have hot swapped failed drives before, but if you are 
using a JBOD setup, I am not sure how that works as seen from Linux, 
though the card handles all of that internally. The biggest thing to 
watch for in the logs with 3ware is are kernel logs and 3dm2 logs for 
the card if you have the support software up.
> > according to the 'Driver / feature matrix'
> > http://linux-ata.org/driver-status.html#matrix
> >
> > driver=sata_mv
> > feature=Device Hotplug
> > feature state=no
>
>  Well spotted, I saw this bit of the same page...
>
>  http://linux-ata.org/driver-status.html#marvell
>
>  ... and it says:
>
>  Driver name: sata_mv
>
>  Summary: Similar to ServerWorks "frodo": per-device queues, full SATA 
>  control including hotplug.
>
>  So I'm a little bit puzzled. Unless it means hotplugging the card 
>  itself?!?
>
>  Anyway, thanks for the pointers.
>
>  
Regards,
Seann

[Christopher Mocock]

Todd Denniston wrote:
>  lsi does not show up on http://linux-ata.org/driver-status.html so
> you 
>  have to figure out what driver supports the card and ask about that driver. 
It's the megaraid_sas driver but it's not shown on the linux-ata.org 
site, so that doesn't bode too well!

> > 3Ware 9550SX, 
>  http://linux-ata.org/driver-status.html#tware
>  apparently you need to ask at the driver maker's site if they support it. 
Aha, I shall do so.

>  according to the 'Driver / feature matrix'
>  http://linux-ata.org/driver-status.html#matrix
>  
>  driver=sata_mv
>  feature=Device Hotplug
>  feature state=no 
Well spotted, I saw this bit of the same page...

http://linux-ata.org/driver-status.html#marvell

... and it says:

Driver name: sata_mv

Summary: Similar to ServerWorks "frodo": per-device queues, full SATA 
control including hotplug.

So I'm a little bit puzzled. Unless it means hotplugging the card itself?!?

Anyway, thanks for the pointers.


-- 
Chris Mocock

chris(a)wavestore.com
www.wavestore.com
Office: [phone]
Mobile: [phone]

Wavelet Technology Ltd., Unit 1 Hayes Metro Centre, Springfield Road, 
Hayes, Middlesex UB4 0LE

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[Todd Denniston]

Christopher Mocock wrote, On 07/17/2008 08:37 AM:
>  Hi list,
>  
>  I'm trying to get SATA hot-swapping to work in Fedora 9 but I'm either 
>  having no luck or doing it wrong.
>  
>  I've tried a variety of disk controllers including an 
>  LSI MegaRaid,  
lsi does not show up on http://linux-ata.org/driver-status.html so you have to 
figure out what driver supports the card and ask about that driver.

>  3Ware 9550SX,  
http://linux-ata.org/driver-status.html#tware
apparently you need to ask at the driver maker's site if they support it.

>  and I'm now working with a Supermicro SAT2-MV8 (Marvell 
>  chipset - sata_mv module). 
according to the 'Driver / feature matrix'
http://linux-ata.org/driver-status.html#matrix

driver=sata_mv
feature=Device Hotplug
feature state=no

>  
>  I was under the (possibly mistaken) impression that if I insert or 
>  remove a disk, I should see something in /var/log/messages. I've also 
>  been running "ls -l /dev/disk/by-path" to see if the device name appears 
>  or disappears, but it never does.
>  
>  Is there any kind of special setup required or should it "just work"?
>  
>  The disks I'm using are either Seagate SATA2 or older Hitachi SATA1 
>  drives, I have a few to play with. The disks are not formatted in any 
>  way as my application treats them as raw block devices. Still, I would 
>  expect to see the contents of /dev/disk/by-path to change when I insert 
>  or remove a disk.
>  
>  When using the 3Ware card, I did get a message from the 3Ware driver 
>  saying that a disk had been removed or inserted, but it didn't change 
>  the contents of /dev/disk/by-path and the message was from the driver, 
>  not the kernel or udev or any other subsystem.
>  
>  I should mention that the disks appear fine if they are inserted before 
>  I boot on all the disk controllers I've tried.
>  
>  Any suggestions gratefully received.
>   
There may be some user space tools you need too.

>  Regards,
>   

-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter