[lug] Reliable SATA server?

[Dan Ferris]

Finally home.

So I have no respect for those 3Ware 9550s.  They ones I have are 
complete trash.  I can't count the number I've replaced because they 
died.  My favorite error is when the server boots and the card comes up 
and says that the card BIOS timed out.

The last one that died I replaced with this (pardon the FreeBSD):

laplace# mfiutil show adapter
mfi0 Adapter:
     Product Name: LSI MegaRAID SAS 9261-8i
    Serial Number: SV11213811
         Firmware: 12.12.0-0073
      RAID Levels: JBOD, RAID0, RAID1, RAID5, RAID6, RAID10, RAID50
   Battery Backup: present
            NVRAM: 32K
   Onboard Memory: 512M
   Minimum Stripe: 8K
   Maximum Stripe: 1M

But like I said, you HAVE to get the BBU or else the card will disable 
the cache no matter what the settings are.  I'm pretty sure the 3Ware 
does the same thing too.

Dan

On 4/21/2012 11:04 AM, Rob Nagler wrote:
> Hi Dan,
>
>> that more than 10% of IO wait continuously means you have a problem.
> This is a disk intensive process (backups), that is, rm, tar, and/or
> cp.  The only thing it should be doing is waiting on disks.
> Controller caches can't improve the performance, because simultaneous,
> continuous, non-sequential reads/writes are running as fast as the
> controller/disks/bus can go. Caches would most likely get in the way
> (we've tested this and write back has no effect).
>
> If you're curious, the code we're using is here:
>
> http://www.bivio.biz/f/bOP/lib/Bivio/Util/Backup.pm
>
> There's another part of the process which involves rsync and cp --link
> --archive which hits a lot of directories, which is not in the above
> code.  The rsync isn't the problem, because it's running over the
> network, and slow enough that it doesn't busy the disks too much.
>
>> Do you use hardware host bus adapters with write back caching, or are
>> you using plain sata drives and mdadm?
> This machine is not using mdadm.  It's a 3ware 9550 with an Intel
> motherboard with one CPU running CentOS 5.7.  I have another machine
> which is using mdadm.  The latter has been crashing pretty frequently,
> and I'm looking for a replacement for it, which is why I emailed this
> list.
>
> Thanks,
> Rob
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