As an update:

new observed behavior:
- RAW disk read performance is phenomenal (200meg/sec)
- Ext3 performance is 100meg/sec and tps in iostat aren't going about
800 (50k with raw disk).

Some added info:
- This system has an oracle database on it and it's tuned for huge
pages..etc (see sysctl posted above)


On Apr 24, 12:07 pm, jnantel <nan...@hotmail.com> wrote:
> If you recall my thread on tuning performance for writes.  Now I am
> attempting to squeeze as much read performance as I can from my
> current setup.  I've read a lot of the previous threads, and there has
> been mention of "miracle" settings that resolved slow reads vs
> writes.  Unfortunately, most posts reference the effects and not the
> changes.   If I were tuning for read performance in the 4k to 128k
> block range what would the best way to go about it?
>
> Observed behavior:
> - Read performance seems to be capped out at 110meg/sec
> - Write performance I get upwards of 190meg/sec
>
> Tuning options I'll be trying:
> block alignment (stride)
> Receiving buffers
> multipath min io changes
> iscsi cmd depth
>
> Hardware:
> 2 x Cisco 3750  with 32gig interconnect
> 2 x Dell R900 with 128gig ram and 1 broadcom Quad (5709) and 2 dual
> port intels (pro 1000/MT)
> 2 x Dell Equallogic PS5000XV with 15 x SAS in raid 10 config
>
> multipath.conf:
>
> device {
>         vendor "EQLOGIC"
>         product "100E-00"
>         path_grouping_policy multibus
>         getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
>         features "1 queue_if_no_path"
>         path_checker readsector0
>         failback immediate
>         path_selector "round-robin 0"
>         rr_min_io 128
>         rr_weight priorities
>
> }
>
> iscsi settings:
>
> node.tpgt = 1
> node.startup = automatic
> iface.hwaddress = default
> iface.iscsi_ifacename = ieth10
> iface.net_ifacename = eth10
> iface.transport_name = tcp
> node.discovery_address = 10.1.253.10
> node.discovery_port = 3260
> node.discovery_type = send_targets
> node.session.initial_cmdsn = 0
> node.session.initial_login_retry_max = 4
> node.session.cmds_max = 1024
> node.session.queue_depth = 128
> node.session.auth.authmethod = None
> node.session.timeo.replacement_timeout = 120
> node.session.err_timeo.abort_timeout = 15
> node.session.err_timeo.lu_reset_timeout = 30
> node.session.err_timeo.host_reset_timeout = 60
> node.session.iscsi.FastAbort = Yes
> node.session.iscsi.InitialR2T = No
> node.session.iscsi.ImmediateData = Yes
> node.session.iscsi.FirstBurstLength = 262144
> node.session.iscsi.MaxBurstLength = 16776192
> node.session.iscsi.DefaultTime2Retain = 0
> node.session.iscsi.DefaultTime2Wait = 2
> node.session.iscsi.MaxConnections = 1
> node.session.iscsi.MaxOutstandingR2T = 1
> node.session.iscsi.ERL = 0
> node.conn[0].address = 10.1.253.10
> node.conn[0].port = 3260
> node.conn[0].startup = manual
> node.conn[0].tcp.window_size = 524288
> node.conn[0].tcp.type_of_service = 0
> node.conn[0].timeo.logout_timeout = 15
> node.conn[0].timeo.login_timeout = 15
> node.conn[0].timeo.auth_timeout = 45
> node.conn[0].timeo.noop_out_interval = 10
> node.conn[0].timeo.noop_out_timeout = 30
> node.conn[0].iscsi.MaxRecvDataSegmentLength = 262144
> node.conn[0].iscsi.HeaderDigest = None,CRC32C
> node.conn[0].iscsi.DataDigest = None
> node.conn[0].iscsi.IFMarker = No
> node.conn[0].iscsi.OFMarker = No
>
> /etc/sysctl.conf
>
> net.core.rmem_default= 65536
> net.core.rmem_max=2097152
> net.core.wmem_default = 65536
> net.core.wmem_max = 262144
> net.ipv4.tcp_mem= 98304 131072 196608
> net.ipv4.tcp_window_scaling=1
>
> #
> # Additional options for Oracle database server
> #ORACLE
> kernel.panic = 2
> kernel.panic_on_oops = 1
> net.ipv4.ip_local_port_range = 1024 65000
> net.core.rmem_default=262144
> net.core.wmem_default=262144
> net.core.rmem_max=524288
> net.core.wmem_max=524288
> fs.aio-max-nr=524288
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