From: Fabio Cannone at Office (fabio.cannone@datamat.it)
Date: Tue Feb 10 2004 - 11:01:06 EST
Hi Boys,
I've s SUN V480 with 4GB of ram running Solaris 8.
I've connected a Sun Storedge 3310 via PCI Dual Ultra3 SCSI adapter.
On top of the raid I've defined a Logical Drive of about 200 GB RAID-5 (4
disk 70 GB each one)
I notice a strange behaviour: If i execute dd if=/dev/zero bs=1024
of=/largefile count=10000 and monitor performance using vmstat I see that
write is running about to 28 Kbytes per second which is really impressive on
internal disk.
On the opposite when i try to perform the same command using as output a
file allocated on the raid I take about 6 KBytes per second which is poor
considering that system should use striping.
Some statistics for both cases are annexed.
COPY ON INTERNAL DISK:
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 2 24 0 74
sd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 32.0 0.0 25058.3 0.0 0.6 17.9 0 52
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
extended device statistics cpu
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 3 23 0 74
sd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 41.0 0.0 25621.2 0.0 0.7 17.1 0 56
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
extended device statistics cpu
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 2 22 2 74
sd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 38.0 0.0 24313.6 0.0 0.7 18.9 0 56
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
COPY ON RAID:
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 1 6 51 42
sd1 10.0 697.0 0.4 5488.4 0.0 43.7 61.7 0 100
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 1.0 0.0 8.0 0.0 0.0 8.8 0 1
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
extended device statistics cpu
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0 8 14 78
sd1 5.0 683.0 1.2 5432.1 0.0 43.1 62.6 0 100
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
extended device statistics cpu
device r/s w/s kr/s kw/s wait actv svc_t %w %b us sy wt id
sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0 7 0 93
sd1 0.0 691.0 0.0 5527.9 0.0 43.2 62.5 0 100
sd31 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
ssd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
Can some help me to better understand the problem ?
Thanks in advance.
Regards.
Fabio Cannone
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