Quoting Chris Schanzle <[EMAIL PROTECTED]>: > Chris wrote:
> I would bet your disks are plenty fast and you have some sort of > software / driver issue, but perhaps the below will help you figure it > out. Keep in mind that your recordings are at most a few megabytes per > second and a single disk should be able to do at least 20-30 MB/sec. Not true. For continuous reads and writes, the throughput of any reasonably modern disk is 20-50 MB/sec. The problem is that once you're recording more than one thing, the writes are no longer continuous. The disk heads have to seek between the locations on the disk to which each video stream is being written to, and as a result throughput will go down the tubes. SATA NCQ should reorder the writes somewhat to improve throughput, but many drives/controllers do not support NCQ yet. Adding extra memory to your backend system (which Linux will use for disk cache) might help. With a big disk cache, the kernel's "elevator" code (which reorders reads and writes somewhat) can more easily write very large chunks between each seek, rather than seeking after only a small amount has been written. > Are your two lvm disks configured as a stripe (raid0) or just a plain > concatenation? Stripes are obviously faster as blocks read/written are > more balanced across the physical devices. See lvcreate(8), -i option. Another good point. Striping will increase disk performance significantly. _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
