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7 responses

22 07 2007
John Call

Aloha Open Systems Storage Guy,

I’m a recent convert to storage administration. I’m having a hard time cutting through the cruft to find the truth. Could you answer some of these questions?

1 – Which is faster, software-based RAID (e.g. Linux md, Windows Dynamic Disks) or hardware-based RAID? One person said that software-based RAID is faster because it has a faster processor and more RAM/cache (something like a Xeon 3.0 Ghz w/ 4Gb or RAM would be typical in my environment). But how could that stack up against my (little bit old) IBM DS4300 Turbo (2Gb cache).

2 – Which is faster, RAID-5 or RAID-10 (or is that RAID-01?) I know everybody says RAID-10, but what about those fancy XOR engines? Or have I fallen prey to marketing?

Thanks for taking a moment to listen to my questions.
Mahalo (Thank you),
John

2 08 2007
John

Aloha Open Systems Guy,

can you take another question from me? I’ve got some questions about OS-drivers for disk subsystems…

What’s up with all the RDAC, MPIO/DSM, and SDD? I’ll try and keep things consistent by limiting my question to one OS (Windows Server 2003).

I’ve heard talk about SDD being superior for the ESS / DS8000 line of storage. It’s apparently not even available in an active/passive array. However, I’ve got a mid-range disk subsystem from IBM, the DS4300 Turbo model.

Until tonight I thought there was only a single choice of multi-pathing driver for me, RDAC. However, when I went about installing my first Windows OS to be SAN-connected I ran into all kinds of new information like SCSIport and STORport and now MPIO / DSM.

Can you help de-mystify this enigma for me?

Mahalo nui loa,
John

7 08 2007
John Call

Aloha Open Systems Storage Guy,

What’s your take on virtualization? VSAN from Cisco, SVC from IBM? What other virtualization products are available from other vendors?

Thanks,
John

21 11 2007
gene

question about SAN interoperability

…2 windows 2003 server sp2 servers, running on HP proliant dl380 g4 each with one single port fiber hba’s. Servers will be clustered to run sql 2005. HBA’s are hp branded- emulex fc2143’s (Emulex id- is lp1150)…SUN SAN has both 6130’s disk array and 3510 array…we want to use disk from both arrays…(betters disks in 6130, slower stuff in 3510)

Do we actually need multipath drivers? (SUN has come out with DSM’s for both these arrays)…any issue using multiple DSM’s if they are requried.

Any known issues with the type of device drivers for the HBAs? Storport versus scsiport…

any help is appreciated

22 05 2008
Paul

Question about multiple servers accessing same disks through a SAN switch

I’m trying to set up a Linux system for server failover where two servers (with SAS HBA) are accessing the same set of disks (jbod) through a SAN switch. First – will this work? If so, what software do I need to run on the servers to keep the two servers from stepping on each other? Do I need multipath support?

21 07 2008
Mike Ault

I had Oracle RAC with ASm running in a RAW configuration on dual 32 bit servers running RedHat 4. I upgraded to dual qla2200 HBAs on each server and they connect through a Brocade 2250 switch to two JBOD disk arrays, a NexStor 18f and a NexStor 8f. I have set up multipath in the multibus configuration and can see the drives as multipath devices in an active-active configuration. I am using OCFS2 for my CRS voting and config disks and that runs fine. When I try to start ASM I can get proper connectivity on the first server that starts up, the second server hands until it eventually errors with a access issue.

I have verified all permissions required are set and can see the disks on both sides using the oracleasm utility. It appears DM is only allowing a single host to access the ASM disks at one time, so when node A starts up and acquires the ASM disks when the ASM instance starts, node B is left hung, visa versa if Node B starts first.

I was told it may be a SCSI reservation issue, but can’t seem to find any information on this. I know people are using this type of configuration to RAID controllers but is the JBOD causing issues? How to get both instances seeing the ASM disks?

Thanks!

30 01 2009
Legal Hallucinogens

I had Oracle RAC with ASm running in a RAW configuration on dual 32 bit servers running RedHat 4. I upgraded to dual qla2200 HBAs on each server and they connect through a Brocade 2250 switch to two JBOD disk arrays, a NexStor 18f and a NexStor 8f. I have set up multipath in the multibus configuration and can see the drives as multipath devices in an active-active configuration. I am using OCFS2 for my CRS voting and config disks and that runs fine. When I try to start ASM I can get proper connectivity on the first server that starts up, the second server hands until it eventually errors with a access issue.

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