SAS Expander Issues on Linux

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npg1981

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Oct 4, 2010
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I'm trying to build a RAID6 array and I'm having problems initializing the array. As far as I can tell I'm doing everything right, so I'm wondering if there are some lingering compatibility issues.

I have a Habey DS-1280 Storage Array enclosure. This is a 12-bay box that has an LSI SASx12A SAS Expander. I currently have 6 Western Digital Black WD2001FASS 2TB drives in the box. I've installed a Sans Digital HA-ARC-13004X mini-SAS host bus adapter in the server; this is an Areca 1300-4x adapter, and I think that it uses either a Marvell 88SE6445 or 88SE6440 chipset. The server is running Mandriva 2010 Spring (2.6.33.7-desktop-2mnb), and I'm using the mvsas module to drive the adapter (v0.8.2).

The server appears to detect the adapter properly, and I can see all of the drives in the box as seperate SCSI devices (/dev/sdb, /dev/sdc, etc). smartctl can read each drive, and it looks like I can use it as a JBOD setup. When I try to use mdadm to set up a RAID array, however, I run into problems. I am able to partition the drives just fine, but when I try to create the array it appears to hang. Checking /proc/mdstat over time shows that the speed of the process starts at 75K/sec and very quickly falls down to 1K/sec, and the ETA just continues to rise. It is never able to create the array and it eventually all the drives get dropped.

My guess is that the mvsas module still has some kinks. Has anyone experienced similar issues? Or any ideas on how to fix this potential issue? Any help at all would be appreciated. If more info about my setup is needed, just ask. Thanks!

(P.S. I know about all the WD TLER issues; I don't really think that's the problem here since I'm trying to use software RAID. But if you really think this could be the cause of the problem, please let me know).
 
I'll give the 1.5gb PHY option a try, I just need to dig up some jumpers first...
 
A little OT but anone notice how similar the Habey and Norco logos are?

Edit: yeah, update that kernel. MVSAS hangs on kernels < 2.6.34.

I never was able to get my SASLP-MV8s to work properly in linux even with kernel update.
 
I was able to try both a more recent kernel (2.6.34.7-tmb-server-2mdv) and jumpering all the drives into 1.5Gb PHY mode, but unfortunately neither has worked so far. Things did seem to look good when I first ran mdadm -- the drive lights on all the drives lit up and /proc/mdstat showed an initial transfer rate of 100K/sec, but it very quickly fell off and the creation process appeared to stall. Any other ideas would be appreciated :)

For reference, the command I'm using to create the array is "mdadm --create /dev/md0 --level=6 --raid-devices=6 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1".
 
From what I heard (I can't remember where) the areca controllers has its own driver and you shouldn't be using the mvsas driver that is in the linux kernel.
 
houkouonchi said:
From what I heard (I can't remember where) the areca controllers has its own driver and you shouldn't be using the mvsas driver that is in the linux kernel.
Click to expand...

I found this on Areca's ftp site, in the SAS_HBA directory:

ftp://ftp.areca.com.tw/SAS_HBA/AP_Drivers/Linux/SourceCode/mvsas.0.8.6/readme.txt
1. This driver source code came from Marvell, we add our product ID to support our HBA.

2. This source code works with kernel version 2.6.25 or later only.

3. Areca HBA patched version avaiable in kernel 2.6.32,
so you do not needed to use this driver code if your kernel version is 2.6.32 or later.
Click to expand...
 
Sorry for the late reply, and thanks for all the suggestions. We were finally able to determine that the issue appears to be driver-related. Unfortunately, the current mvsas driver doesn't have very good (if any) support for SAS expanders. The version included in the most recent Mandriva kernel was 0.8.2, but even the most recent version (0.8.6) doesn't appear to have robust expander support (the 0.8.6 readme.txt indicates that multipliers and expanders with more than two layers are not supported).

We eventually scrapped the ARC-13004X controller and went with a more linux-friendly one: the LSI SAS 3801E controller. We are using version 4.24 of mptsas and the controller is working great -- it found all the drives and I was able to start initializing our array on the first try. So I guess the moral of the story is that mvsas has a little ways to go.
 
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