Carlos E. R. wrote:
--- If you compress email, it makes grep'ing through it much slower...
Then it is compressed too much, or it is not coded right: one core decompressing, one core analysing.
--- Like I said, gzip -0 is "too much" -- any compression will be slower. 'grep' from a file in memory @2.7GB -- takes 1.24s. That gives 2.12TB/s. So far none of the compress utils exceed ~100MB/s
Really depends on your disks and backup media.
Yes, it does. For instance, with this laptop I have to backup via usb cable, which is slow. Compressing does make a difference.
--- Have you run 'dd' tests to see what max speeds are? remember to use direct i/o for writes, though best to test with and without DIO, as a USB disk might be slow enough to get some benefit from the linux disk cache. But to give you an idea of how little overhead it takes to slow things down -- writing a 8GB to a file through the disk cache (conv=fdatasync): 473.5MB/s, writing a file direct (oflag=direct): 898MB/s. (All figures use 2**10 based prefixes, not 10**3). To get closer, try to make sure your destination file doesn't have holes in it. FWIW, I used:
time bash -c 'dd if=/dev/zero of=1TB bs=64M count=128 oflag=direct
xz, lzma, 7z (all similar), bzip2 ncompress(compress), lzop (fastest I have, but only about 2x gz), and likely the slowest (but maybe best compression): rzip. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org