Hi All,
With no compression I am filling a disk to 77% to see how fast a scrub will run with no fragmentation. I figured I would see each disk start at the fast end and get slower until the dd was finished. 6 or so hours to fill it and 2 hours for the scrub. 12 drive, 3.0TB sas 7200 rpm 3.5 drives. What I saw was a saw tooth and I am not sure why:
This is how I filled the disk :
for i in $(awk 'BEGIN {for(i=0;i<1300;i++) print i}'); do dd if=/dev/zero of=ddfile$i.dat bs=2048k count=5100; done
This is the volume in question:
Filesystem Size Used Avail Capacity Mounted on
detvolaa 3.2T 92K 3.2T 0% /mnt/detvolaa
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
detvolaa 16.3T 12.6T 3.66T - - 0% 77% 1.00x ONLINE /mnt
zpool status -v detvolaa
pool: detvolaa
state: ONLINE
scan: resilvered 14.7G in 0 days 00:02:31 with 0 errors on Mon Dec 17 07:04:04 2018
config:
NAME STATE READ WRITE CKSUM
detvolaa ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
gptid/6c34431d-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/6d6b2014-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
gptid/95d6aa2d-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/97c50e2b-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
gptid/b0e198cd-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/b60c38f7-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
gptid/d051b1c1-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/d1dcaec9-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-4 ONLINE 0 0 0
gptid/29df61ea-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/2b8baab9-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-5 ONLINE 0 0 0
gptid/3c57e2f7-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/3e0c9d1f-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
errors: No known data errors
root@freenas[/mnt/detvolaa/noComp]#
With no compression I am filling a disk to 77% to see how fast a scrub will run with no fragmentation. I figured I would see each disk start at the fast end and get slower until the dd was finished. 6 or so hours to fill it and 2 hours for the scrub. 12 drive, 3.0TB sas 7200 rpm 3.5 drives. What I saw was a saw tooth and I am not sure why:
This is how I filled the disk :
for i in $(awk 'BEGIN {for(i=0;i<1300;i++) print i}'); do dd if=/dev/zero of=ddfile$i.dat bs=2048k count=5100; done
This is the volume in question:
Filesystem Size Used Avail Capacity Mounted on
detvolaa 3.2T 92K 3.2T 0% /mnt/detvolaa
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
detvolaa 16.3T 12.6T 3.66T - - 0% 77% 1.00x ONLINE /mnt
zpool status -v detvolaa
pool: detvolaa
state: ONLINE
scan: resilvered 14.7G in 0 days 00:02:31 with 0 errors on Mon Dec 17 07:04:04 2018
config:
NAME STATE READ WRITE CKSUM
detvolaa ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
gptid/6c34431d-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/6d6b2014-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
gptid/95d6aa2d-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/97c50e2b-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
gptid/b0e198cd-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/b60c38f7-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
gptid/d051b1c1-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/d1dcaec9-00c1-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-4 ONLINE 0 0 0
gptid/29df61ea-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/2b8baab9-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
mirror-5 ONLINE 0 0 0
gptid/3c57e2f7-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
gptid/3e0c9d1f-00c2-11e9-8345-246e968a4118 ONLINE 0 0 0
errors: No known data errors
root@freenas[/mnt/detvolaa/noComp]#