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Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?
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I'm hoping some people here can give me recommendations on SCSI RAID cards. My minimum requirement is that it can handle 10 U160 SCSI drives per channel. 2 or more channels per card would be nice, but not necessary. I've discovered that the Dell PERC3/DC using the Megaraid driver is unstable under high loads, so something similar from Adaptec or 3WARE would be ideal. On-card cache RAM isn't really necessary, 64-bit PCI would be nice. This will be used in a MySQL database server. I realize that the Linux kernel supports a lot of hardware RAID controllers, but I'm hoping for some recommendations from people with real-world experience.
In case you're wondering if I've considered software RAID, the answer is yes. It's great, except when it comes to recovering from a failed drive without a reboot. Then it's a pain in the ass. If I have 3 drives (sda, sdb, and sdc) and sdb fails, I can pull it, replace it, and force a SCSI bus rescan through an awkward mechanism involving /proc/scsi, but then the new drive shows up as sdd, not sdb. It just seems so clumsy compared to hardware RAID that just handles everything behind the scenes.
I've had great success with the Compaq/HP controllers based on the symbus? (I dont have the right spelling) chipsets.
I have an older adaptec 2100S U160 single channel that has been up in a Redhat 6.2 box for years at a time. My only compliant here is that when a drive goes out I am forced to reboot the box. Over the years I have replaced about 3 drives, never any data lose. (It's not a hot swap chassis)
Most controllers are pretty good until you really load them and than they fall apart to different degrees.
I'm a IT manager for a company that develops a product on that runs RHEL with Mysql, apache for a custom transaction application. I have placed somewhere around 200 of them in pretty high transaction load enviroments, 6+ transactions a second. In my labs we have tested out with over 90/s on some pretty lowend hardware. Keep in mind what I call a transaction on what you can a transaction will likely be completely different. Just remember to test as much as you can before deployment.
Thanks for the reply! I'll definitely look into the Compaq/HP controllers, and maybe that Adaptec controller as well. The chassis we have are hot-swap capable SCA types, luckily. As for testing, I have a stable MySQL install under Windows Server 2003 which I'll run as a MySQL master and run the Linux box as a slave. That way if the Linux box self-destructs under load, no big deal. I'll do some stress-testing, too. Re-indexing one of my databases tables with about 15G of data in 397M records usually brings out the hardware bugs if they're load-related.