Very slow disk speed / mpt0: LSILogic SAS/SATA Adapter

Matej Šerc matej.serc at
Wed Jun 17 12:01:35 UTC 2009


we have a HP ProLiant server with RAID 0/1 controller onboard. It is
detected as mpt0 (I have attached a part of dmesg output at the end of the
mail). As reported by some already (,
we are also getting extremely slow write speeds. I read somewhere that there
are some improvements which could solve the situation in 7.2 (our system has
7.1 installed and I am currently unable to turn it off and it will stay so
for at least 3 months).

There are some information that setting hw.mpt.enable_sata_wc=1 solves the
write speed (it actually does as I tested!), but I would like to know more
about how danger that option is. We are using softupdates and now have this
hw.mpt.enable_sata_wc=0, after reading that it might be very dangerous when
using sata_wc=1.

I am really looking forward to getting more information about this, it is
actually driving me nuts. We have a number of other servers and there are no
problems with RAID controllers at all. And as I said, I cannot actually turn
of this machine and bring it back to reinstall new OS.

Thank you very much for your comments and thoughts,

The server model is ML110G5.

mpt0: <LSILogic SAS/SATA Adapter> port 0xd000-0xd0ff mem
0xfcefc000-0xfcefffff,0xfcee0000-0xfceeffff irq 16 at device 0.0 on pci5
mpt0: [ITHREAD]
mpt0: MPI Version=
mpt0: Capabilities: ( RAID-0 RAID-1E RAID-1 )
mpt0: 1 Active Volume (2 Max)
mpt0: 3 Hidden Drive Members (10 Max)

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