Why open-iscsi has 2x slower writes than Samba via 10G Ethernet?Slow iSCSI speeds between WinServer2016 and...
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Why open-iscsi has 2x slower writes than Samba via 10G Ethernet?
Slow iSCSI speeds between WinServer2016 and Win10 over 10G Ethernet
On my local file server I have raid-6 on 7x HDD drives.
dd if=/dev/zero of=tempfile bs=1M count=2048 conv=fdatasync
Local speed test gives me 349 MB/s write speed.
Remote writes to Samba from SSD (>2Gb/s read speed) gives me 259 MB/s writes.
But remote writes to iSCSI drive (on Win10 iSCSI initiator) gives me mere 151 Mb/s writes.
raid6 config - 128K chunk size, stripe_cache_size = 8191. Write intent bitmap is on SSD (Samsung 860 PRO, 4096K bitmap chunk).
Array mounted with options: rw,noatime,nobarrier,commit=999,stripe=128,data=writeback
open-iscsi setup: target is based on a 4Tb file.
Any hints why iSCSI is slower than Samba on writes?
Any hints how to improve iSCSI writes speed?
I assume it has something to do with desire of open-iscsi to flush writes to disk after each operation, which increases write amplification on raid6 due to excessive parity rewrites. But I am not sure how to fix it. Speed it more important than safety of currently written data in case of power outage.
As a side note older ietd iSCSI target had the ability to enable write-back mode (using IOMode=wb), and sustained write speed was much faster. Unfortunately, it seems to be currently unmaintained.
iscsi software-raid mdadm raid5 open-iscsi
asked 6 mins ago
BarsMonsterBarsMonster
742921
add a comment |
On my local file server I have raid-6 on 7x HDD drives.
dd if=/dev/zero of=tempfile bs=1M count=2048 conv=fdatasync
Local speed test gives me 349 MB/s write speed.
Remote writes to Samba from SSD (>2Gb/s read speed) gives me 259 MB/s writes.
But remote writes to iSCSI drive (on Win10 iSCSI initiator) gives me mere 151 Mb/s writes.
raid6 config - 128K chunk size, stripe_cache_size = 8191. Write intent bitmap is on SSD (Samsung 860 PRO, 4096K bitmap chunk).
Array mounted with options: rw,noatime,nobarrier,commit=999,stripe=128,data=writeback
open-iscsi setup: target is based on a 4Tb file.
Any hints why iSCSI is slower than Samba on writes?
Any hints how to improve iSCSI writes speed?
I assume it has something to do with desire of open-iscsi to flush writes to disk after each operation, which increases write amplification on raid6 due to excessive parity rewrites. But I am not sure how to fix it. Speed it more important than safety of currently written data in case of power outage.
As a side note older ietd iSCSI target had the ability to enable write-back mode (using IOMode=wb), and sustained write speed was much faster. Unfortunately, it seems to be currently unmaintained.
iscsi software-raid mdadm raid5 open-iscsi
asked 6 mins ago
BarsMonsterBarsMonster
742921
add a comment |
On my local file server I have raid-6 on 7x HDD drives.
dd if=/dev/zero of=tempfile bs=1M count=2048 conv=fdatasync
Local speed test gives me 349 MB/s write speed.
Remote writes to Samba from SSD (>2Gb/s read speed) gives me 259 MB/s writes.
But remote writes to iSCSI drive (on Win10 iSCSI initiator) gives me mere 151 Mb/s writes.
raid6 config - 128K chunk size, stripe_cache_size = 8191. Write intent bitmap is on SSD (Samsung 860 PRO, 4096K bitmap chunk).
Array mounted with options: rw,noatime,nobarrier,commit=999,stripe=128,data=writeback
open-iscsi setup: target is based on a 4Tb file.
Any hints why iSCSI is slower than Samba on writes?
Any hints how to improve iSCSI writes speed?
I assume it has something to do with desire of open-iscsi to flush writes to disk after each operation, which increases write amplification on raid6 due to excessive parity rewrites. But I am not sure how to fix it. Speed it more important than safety of currently written data in case of power outage.
As a side note older ietd iSCSI target had the ability to enable write-back mode (using IOMode=wb), and sustained write speed was much faster. Unfortunately, it seems to be currently unmaintained.
iscsi software-raid mdadm raid5 open-iscsi
asked 6 mins ago
BarsMonsterBarsMonster
742921
On my local file server I have raid-6 on 7x HDD drives.
dd if=/dev/zero of=tempfile bs=1M count=2048 conv=fdatasync
Local speed test gives me 349 MB/s write speed.
Remote writes to Samba from SSD (>2Gb/s read speed) gives me 259 MB/s writes.
But remote writes to iSCSI drive (on Win10 iSCSI initiator) gives me mere 151 Mb/s writes.
raid6 config - 128K chunk size, stripe_cache_size = 8191. Write intent bitmap is on SSD (Samsung 860 PRO, 4096K bitmap chunk).
Array mounted with options: rw,noatime,nobarrier,commit=999,stripe=128,data=writeback
open-iscsi setup: target is based on a 4Tb file.
Any hints why iSCSI is slower than Samba on writes?
Any hints how to improve iSCSI writes speed?
I assume it has something to do with desire of open-iscsi to flush writes to disk after each operation, which increases write amplification on raid6 due to excessive parity rewrites. But I am not sure how to fix it. Speed it more important than safety of currently written data in case of power outage.
As a side note older ietd iSCSI target had the ability to enable write-back mode (using IOMode=wb), and sustained write speed was much faster. Unfortunately, it seems to be currently unmaintained.
iscsi software-raid mdadm raid5 open-iscsi
iscsi software-raid mdadm raid5 open-iscsi
asked 6 mins ago
BarsMonsterBarsMonster
742921
asked 6 mins ago
BarsMonsterBarsMonster
742921
edited 1 min ago
BarsMonster
asked 6 mins ago
BarsMonsterBarsMonster
742921
asked 6 mins ago
BarsMonsterBarsMonster
742921
asked 6 mins ago
BarsMonsterBarsMonster
742921
742921
add a comment |
add a comment |
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