ZFS (and quota)

[Dag-Erling Smørgrav]

Johan Ström <johan at stromnet.se> writes:
> Dag-Erling Smørgrav <des at des.no> writes:
> > des at ds4 ~% sudo zfs create raid/q
> > des at ds4 ~% sudo zfs set quota=1m raid/q
> > des at ds4 ~% sudo dd if=/dev/zero of=/raid/q/test bs=65536
> > dd: /raid/q/test: Disc quota exceeded
> > 16+0 records in
> > 15+0 records out
> > 983040 bytes transferred in 2.533990 secs (387942 bytes/sec)
> > des at ds4 ~% zfs list raid/q
> > NAME     USED  AVAIL  REFER  MOUNTPOINT
> > raid/q  1.03M      0  1.03M  /raid/q
> With the  bs=65536 parameter it works as expected, I get Disk quota
> exceeded. Without it it just keeps on running until I interrupt it

It seems that with small block sizes, it becomes increasingly slow as
the partition fills up.  You can easily see that by pressing ^T while dd
is running; you will see that it still makes progress, but very slowly.

des at ds4 ~% sudo dd if=/dev/zero of=/raid/q/test
load: 0.18  cmd: dd 20250 [zfs:(&tx->tx_quiesce_done_cv)] 0.01u 0.48s 0% 1192k
17245+0 records in
17244+0 records out
8828928 bytes transferred in 18.743790 secs (471032 bytes/sec)
load: 0.17  cmd: dd 20250 [zfs:(&tx->tx_quiesce_done_cv)] 0.01u 0.49s 0% 1212k
17273+0 records in
17272+0 records out
8843264 bytes transferred in 23.642442 secs (374042 bytes/sec)
load: 0.24  cmd: dd 20250 [zfs:(&tx->tx_quiesce_done_cv)] 0.01u 0.51s 0% 1212k
17406+0 records in
17405+0 records out
8911360 bytes transferred in 45.053364 secs (197796 bytes/sec)
load: 0.15  cmd: dd 20250 [zfs:(&tx->tx_quiesce_done_cv)] 0.01u 0.55s 0% 1212k
17601+0 records in
17600+0 records out
9011200 bytes transferred in 76.173965 secs (118298 bytes/sec)
load: 0.06  cmd: dd 20250 [zfs:(&tx->tx_quiesce_done_cv)] 0.02u 0.60s 0% 1212k
17906+0 records in
17905+0 records out
9167360 bytes transferred in 126.020690 secs (72745 bytes/sec)
^C18259+0 records in
18258+0 records out
9348096 bytes transferred in 185.266755 secs (50457 bytes/sec)

DES
-- 
Dag-Erling Smørgrav - des at des.no