Hi Roger / All --
ls -la -rw-r--r-- 1 root root 8130652160 2008-04-08 11:07 sys.dump
dd if=sys.dump of=/dev/null 15880180+0 records in 15880180+0 records out 8130652160 bytes (8.1 GB) copied, 28.5627 s, 285 MB/s
I did the test you recommend and got the above. I think I could come close to flooding that interface. I was looking at the:
http://www.newegg.com/Product/Product.aspx?Item=N82E16816103066
$200.00 (1) Adaptec 2250300-R PCIe x 1 SCSI 29320LPE Kit - new scsi card to increase bandwidth on lto4 tape system. (my current card is U160/133 pci-x, but i have a PCIe x 1 free)
I haven't found any major problems searching the web on this card. Do you have a recommendation on a LSI card?
Thanks much for all you input, I'm mostly a lurker of the list, but I've learned mucho and keep reading and learing!
-- Gary
Hi Roger --
Thanks for the quick responses. The backup unit is a Overland arcvault 12 w/lto4 drive. The lto4 have, I think, 120MBps (Native)/240MBps (compressed), so no gain using U320 interface? I'd guess the max thru put would be 120MBs, with the compressed rate just accomplished because of data compressing. Sorry to be thinking out loud here, but this does help!
-- G
Well, if that is what you have, you did spend some decent money on it.
The important part it LTO4. Native speed is 432GB/hr, or 120MB/second, if you get good compression and you have a *FAST* disk subsystem, then you could use that speed, I would test doing a backup with you backup software to /dev/null and see what the actual disk speed is, if you are backing up a lot of small files you won't be able to use all of the speed, or if the files are fragmented on disk you may not be able to use that speed.
If you data does not compress good you won't be able to go over 160 MB/second either.
You would have to be getting the data locally from a high-end disk subsystem, and you have to have big files, and you would have to data that was compressible. Overall you have to be pretty careful to get something that will read at 120MB/second and also write out to a tape at 120MB/second, you have to make sure the PCI-X slots are not shared with each other, and that all other subsystems can do it.
And if your current SCSI card is PCI (not-X, not-64bit) then the actual limit is probably < 132MB/sec (PCI limit).
I would try what you have and see what speed you are getting, if you run within 20-30 of the limit you may be hitting the limit, if you are much below that you have other issues.
Generally though I have had good luck with the LSI cards, I have used their SCSI, SAS, and fiber channel cards of various sorts. If I was getting one of those new I would have got either a SAS or a Fiber channel interface for it (if it was available), as they tend to be less trouble than SCSI.
Roger
gary artim wrote:
Hi Roger / All --
ls -la -rw-r--r-- 1 root root 8130652160 2008-04-08 11:07 sys.dump
dd if=sys.dump of=/dev/null 15880180+0 records in 15880180+0 records out 8130652160 bytes (8.1 GB) copied, 28.5627 s, 285 MB/s
I did the test you recommend and got the above. I think I could come close to flooding that interface. I was looking at the:
So long as that was coming off of the disk, and you don't have enough ram that some portion of it could be coming from the memory disk cache it is ok, on a machine with more than 8GB of ram if you just made the file, and/or did several tests there is a very high probability that all or part of it is coming from cache and a meaningless test.
http://www.newegg.com/Product/Product.aspx?Item=N82E16816103066
$200.00 (1) Adaptec 2250300-R PCIe x 1 SCSI 29320LPE Kit - new scsi card to increase bandwidth on lto4 tape system. (my current card is U160/133 pci-x, but i have a PCIe x 1 free)
Keep in mind that PCIe x 1 is 2.5 Gbit per second (around 250MByte/second), actually slower than any typical PCIX slot at any speed (PCIX64 x 66 is 528MByte per second), so you may not get much more than with the U160 card that you started with.
I haven't found any major problems searching the web on this card. Do you have a recommendation on a LSI card?
So long as you stay with Adaptec or LSI and make sure that the driver is in the default kernel (no add on drivers) you should be fine.
Thanks much for all you input, I'm mostly a lurker of the list, but I've learned mucho and keep reading and learing!
-- Gary