Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
De:drbd-user-bounces at lists.linbit.com
Para:"drbd-user" drbd-user at lists.linbit.com
Cópia:
Data:Thu, 23 Sep 2004 15:09:37 +0200
Assunto:Re: [DRBD-user] drbd tranfer limitations (random and sequential acccess) using raw
> / 2004-09-23 09:47:48 -0300
> \ crsurf:
> > > / 2004-09-23 09:01:50 -0300
> > > \ crsurf:
> > > > Hello list
> > > > I?m using drbd in a Gigabit network (crossover cable) and when I
> > > > synchronize data (sequential read/write) the tranfer hit to 30~40
> > > > Mb/s, but when I make inserts into database (random read/write) that
> > > > access drbd device via raw, the transfer rate hit only 5~6 Mb/s.
> > > > Exists some way to improve this performance? I increased the
> > > > sndbuf-size to 256K, but no such effect. I increase interface MTU to
> > > > 9000 and no such effect too. One database process that run in 4 min.
> > > > without replication, run in 30 min. with replication. Now I?m trying
> > > > using filesystem jfs instead raw to view if the performance will be
> > > > improved.
> > > > Maybe sync-nice can help us?
> > >
> > > I am not sure which transfer rate you are talking about.
> > > the throughput of your applications, or the resync throughput?
> > >
> >
> > With resync tha transfer hit 40~50 Mb/s, afer I changed MTU.
> >
> > > or the resync throughput while you have resynchronization and
> > > applications running concurrently?
> > >
> >
> > And when I make a insert into database the transfer hit to 4~6 Mb/s,
> > without full synchronization, only online synchronization.
>
> which transfer.
> sorry, again I don't get you here.
>
> is it that your data base has a write throughput of 6 MB,
> or that drbd resync throughput drops to 6 MB while the database is
> running?
Yes is it, when using database throughput not pass 6 Mb/s.
>
> how do you measure?
I´m using iptraf to view network traffic and is that wich says the throughput I mencioned before (4~6 Mb when inserting in database and 40~50 Mb/s when doing SyncingAll).
This is the output of iostat on primary server
avg-cpu: %user %nice %sys %iowait %idle
0.79 0.00 1.54 3.28 94.39
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 120.44 5271.05 1872.72 290326040 103148100
sda1 0.00 0.05 0.01 2928 424
sda2 120.43 5271.00 1872.71 290323088 103147676
This is the output of iostat on seconday server
avg-cpu: %user %nice %sys %iowait %idle
0.32 0.00 1.82 3.58 94.27
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 212.38 1159.70 6143.03 84933272 449898916
sda1 0.00 0.02 0.01 1736 416
sda2 212.38 1159.67 6143.02 84931456 449898500
>
> and if you are concerned about your database application throughput,
> how does it compare to the figures you get when not using drbd?
When using drbd connected to secondary the time of an process is 20~30 min.
When using with drbd disconnect to secondary the time is 4~5 min.
On primary server I have a RAID 10 (0+1) and on secondary server I have only one disk SCSI. Maybe this causing delay too?
>
> > > and when you talk about sync-nice, you are using drbd 0.6 ?
> >
> > Yes, I?m using 0.6.13
> >
> > >
> > > maybe you want to use 0.7 instead. it reduces the amount of data
> > > transfered to a minimum, thus reducing the time for resynchronization to
> > > some one to three minutes, typically.
> >
> > Well, I?m already compiled 0.7.4, but my question is: I can use the
> > config file of 0.6 in 0.7? And the drbdsetup commands to replicate and
> > define primary node are the same?
>
> you have to adopt the conf file, syntax has changed.
> should be easy enough.
> though, make sure you first read
> upgrade_0.6.x_to_0.7.0.txt and
> upgrade_0.7.0_to_0.7.1.txt
>
> I don't understand what you mean by "commands to replicate".
> in general, the interface for 0.7 is the new drbdadm command,
> and it has a nice little english manpage that should even be complete.
>
Tanks in advance
>
> Lars Ellenberg
>
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