On Jul 21, 2004, at 4:25 PM, Kevin P. Fleming wrote:
Scott Laird wrote:
That hasn't been my experience at all. Frankly, I've never seen a cheap (<$3k) hardware RAID controller that can touch software RAID's performance on Linux, especially in "challenging" setups, like RAID-5. Sure, software RAID eats more CPU, but most PCs have CPU to spare these days. Would you rather eat 10% of one of your Xeon CPUs to get 200 MB/sec or 100% of an Intel 960 to get 15 MB/sec?
While this is certainly true, in the context of Asterisk you also have to consider the extra PCI bus usage for all this data going back and forth to the drives while the RAID parity/mirror stuff is being done.
Sure. Particularly after this week's echo discussion.
However, there are three ways around this. First, modern chipsets don't route their on-board IDE ports over a PCI bus--they're local to the southbridge and routed over a high-speed link between the north and south bridges. Second, most of the current server boards on the market have 3 PCI busses--typically 2 PCI-X busses and 1 PCI 32/33 bus. So, just make sure that you don't put your IDE drives onto the same bus as your telephony cards, and you should be fine. One quick way to check--you can only have 1 PCI-X 133 slot per bus. So, if a board advertises two PCI-X 133 slots, then you know that you have at least 2 PCI-X busses. PCI-X 100 allows 2 slots, and PCI-X 66 allows 4.
One more note: at a previous job, I actually had problems with 3ware 6000-series cards and PCI latency. I had 3 4-port 3ware cards sharing a bus with an Intel GigE card, and under heavy disk load, I was losing packets due to PCI latency. Since these were primarily NFS servers, and NFS is hyper-sensitive to packet loss, this killed my performance. Turning down the PCI latency timer on the 3ware cards helped quite a bit. Modern systems with multiple busses shouldn't have this problem.
Scott
_______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
