Date: Fri, 24 Apr 2009 22:53:53 +0200 From: Alexei Troussov <erleya@gmail.com> To: freebsd-geom@freebsd.org Subject: gjournal+gstripe+gmirror question Message-ID: <B1D3FED7-AC64-453A-99AE-A6C8F6CCC8F3@gmail.com>
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Hello All,
I decided to build multi-terabyte data storage (file server) using 4 x
1Tb disks. No special raid controller is used, FreeBSD 7.1 is running
on another disk, so the disk array is going to be used for file
storage only.
So, I tried several combinations of gmirror/gstripe and put gjournal
on it:
1) two mirrors and stripe on them
2) two stripes and mirror on them
Both configurations gave excellent I/O speed (around 100Mb/sec), and I
chose the first one as it needs less time to resync disks when one of
the mirrors fails. To make picture more complete, I didn't try graid3
because it seems to load CPU more than configs above, which is not
good for my barebone :)
Now when my top-level gstripe gets "gjournal"-ed, I see relatively
poor write speed around 20-30 Mb/sec.
As far as I understand from man gjournal and some posts here,
performance usually drops about 40-50%, but what I have is much worse...
Are there a better way to configure/tune the whole thing?
Thanks in advance!
PS Here is my current playground config:
--------
> gmirror list
Geom name: gm0
State: COMPLETE
Components: 1
Balance: round-robin
Slice: 4096
Flags: NONE
GenID: 0
SyncID: 1
ID: 2111539126
Providers:
1. Name: mirror/gm0
Mediasize: 1000204885504 (932G)
Sectorsize: 512
Mode: r1w1e2
Consumers:
1. Name: ad10
Mediasize: 1000204886016 (932G)
Sectorsize: 512
Mode: r1w1e1
State: ACTIVE
Priority: 0
Flags: NONE
GenID: 0
SyncID: 1
ID: 3300348150
2. Name: ad12
Mediasize: 1000204886016 (932G)
Sectorsize: 512
Mode: r1w1e1
State: ACTIVE
Priority: 0
Flags: NONE
GenID: 0
SyncID: 1
ID: 4291633068
Geom name: gm1
State: COMPLETE
Components: 2
Balance: round-robin
Slice: 4096
Flags: NONE
GenID: 0
SyncID: 1
ID: 835525163
Providers:
1. Name: mirror/gm1
Mediasize: 1000204885504 (932G)
Sectorsize: 512
Mode: r1w1e2
Consumers:
1. Name: ad11
Mediasize: 1000204886016 (932G)
Sectorsize: 512
Mode: r1w1e1
State: ACTIVE
Priority: 0
Flags: NONE
GenID: 0
SyncID: 1
ID: 1770536936
2. Name: ad13
Mediasize: 1000204886016 (932G)
Sectorsize: 512
Mode: r1w1e1
State: ACTIVE
Priority: 0
Flags: NONE
GenID: 0
SyncID: 1
ID: 922042393
> gstripe list
Geom name: gs0
State: UP
Status: Total=2, Online=2
Type: AUTOMATIC
Stripesize: 131072
ID: 1106325435
Providers:
1. Name: stripe/gs0
Mediasize: 2000409591808 (1.8T)
Sectorsize: 512
Mode: r1w1e1
Consumers:
1. Name: mirror/gm0
Mediasize: 1000204885504 (932G)
Sectorsize: 512
Mode: r1w1e2
Number: 0
2. Name: mirror/gm1
Mediasize: 1000204885504 (932G)
Sectorsize: 512
Mode: r1w1e2
Number: 1
--------
Have a nice day,
Alex
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