TCP Offload and Linux, Plus Goodies

Short answer - not happening.  Another short answer: unwanted, unneeded.

At least, that's the sentiment from the kernel development team.  That works for me - cheaper cards work just as well!  I can get about 1.6Gbit/sec during bidirectional bandwidth tests using iperf...probably more if I do a direct-connect (will have to try that one out!!).

In other news - handy piece of knowledge: you can load the Linux bonding driver multiple times to configure multiple bonds with different settings!  YAY!

HBA adapters act as iSCSI initiators and manage the connection while presenting a block device to the operating system.  Note to self: don't try to use them as ethernet cards.  Might as well USE ethernet cards, since many of my systems don't have that much space in them.

I started using micro USB sticks (the really short ones that stick out of the computer by no more than about 1/4 inch) as the boot media for my new servers.  Works good, when it works.  The trick is getting the install right.  Some notes:

• Make sure you turn off DOS-compatibility or you'll find that GRUB can't stuff itself into the appropriate region of the device.
• When copying an existing boot device to a RAID device, dd the file system over  (if possible) and then extend it: dd if=/dev/sda1 of=/dev/md1
• The reason is because GRUB gets burned with UUIDs by the Ubuntu install process, and expects to find those later during boot.  By creating a new file system on the RAID, you'll get a new UUID or have to hand-copy the old one over.
• If turning off DOS-compatibility doesn't work, just push the start of the first partition back a cylinder or two.  That should open enough space.
• If you have two devices in RAID for /boot, and want to replace them with USB sticks:
• Add the two devices, and then fail-rebuild your way on to them by failing one old device at a time.  Do NOT fail them both at once!
• Make sure to run grub-install /dev/sd_ to install the actual bootloader.  Do this for both devices in the RAID.

Why would anyone want to boot off USB devices?  Well, it's fast, and /boot rarely gets written to, and I can put my entire system on the RAID with the rest of the storage, meaning it too will be privy to array-wide hot-spares and all the redundancy that comes with RAID-6.  Now, that being said, I'm still keeping backups...