Category Archives: read_max

UFS read-ahead

After 10 years of it being conservatively tuned, I've recently increased the default read-ahead (vfs.read_max) in FreeBSD from 128 KiB to a whopping 512 KiB. And of course, I have received an e-mail from a concerned developer asking if that is perhaps too high :)

How much impact can read_max have I'll try to illustrate on this excellent example on a machine I'm currently configuring.