# poweredge 840 RAID1 SAS5iR controller [solved]

## huuan

I'm about to install gentoo hardened on a Dell Poweredge 840  with a SAS5iR hardware RAID controller set for RAID1  with 2x80 G SATA hdd

Does gentoo support hardware RAID controllers like this?

JohnnyLast edited by huuan on Thu Mar 22, 2007 2:39 am; edited 1 time in total

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## Navisence

 *huuan wrote:*   

> I'm about to install gentoo hardened on a Dell Poweredge 840  with a SAS5iR hardware RAID controller set for RAID1  with 2x80 G SATA hdd
> 
> Does gentoo support hardware RAID controllers like this?
> 
> Johnny

 

I think it's more a question if the kernel is supporting the SAS 5iR controller. According to http://lists.centos.org/pipermail/centos/2006-October/070929.html, it seems to do so through the megaraid_sas driver. I'm quoting from a 2.6.17 kernel here:

```
Symbol: MEGARAID_SAS [=n]

LSI Logic MegaRAID SAS RAID Module

  Defined at drivers/scsi/megaraid/Kconfig.megaraid:78

  Depends on: PCI && SCSI

  Location:

    -> Device Drivers

      -> SCSI device support

        -> SCSI device support (SCSI [=y])

          -> SCSI low-level drivers
```

Anyway, I'm interested to hear from you if you tried this and if it worked out...

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## huuan

Device Drivers --->

  Fusion MPT device support  --->

     <*> Fusion MPT ScsiHost drivers for SAS

I found what to use here :

https://forums.gentoo.org/viewtopic-t-545602-highlight-poweredge.html

when I'm done in a week or two I'll post more details of my experience with the install.

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## Navisence

Ok, thanks for the reference to the correct driver. I'm looking into buying a PE860 within a couple of days and I want to make sure the hardware is supported in the kernel.

About the 5iR RAID1 with 2 SATA drives, I just found this thread on the Dell forums: http://www.dellcommunity.com/supportforums/board/message?board.id=pes_hardrive&thread.id=24696&c=us&l=en&cs=19&s=dhs.

It's about performance loss when writing to the mirrored SATA disks due to the disk write cache being disabled in this kind of setup. Could you or anyone else comment on this? Any experiences or is it rather unimportant when you're mostly serving a relatively small website?

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## huuan

I just found that iozone is in portage so I'll test the controller + drives if you like. Any specific test you'd like run?

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## Navisence

Seems to be a great tool to test these things! Didn't know it before.

Because of the issue covered on the DELL forums, I'm mostly interested in the write performance. I'm wondering how this looks without the write caches on the SAS 5iR controller.

The server has been ordered and I expect this not to be too big of an issue for the intended application. I hope to be able to test things in 2 weeks myself.  :Smile: 

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