[DRBD-user] drbd performance issue on SATA

Eduardo Diaz - Gmail ediazrod at gmail.com
Thu Jan 5 00:08:52 CET 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi, don't have a 1Gb network??? you "need" a 1GB network at least
because the 100 is veryyyyy slow... for a speed configuration...

Now I have a Active-Active (what filesystem are you using? ocfs2??),
If you send me the test that you make I can run in my own server...
(somthink ease, please :) ).


On Wed, Jan 4, 2012 at 1:18 PM, François Delpierre
<francois.delpierre at pivert.org> wrote:
> I noticed I did not reply to the list. So, here is the copy :
>
> Hi Eduardo,
>
> When I had these horrible performances I was not in a good situations :
> - One 2GB disk SSD 7200RPM per node.
> - DRBD 8.3, Protocol C, Active-Active
> - 2 Network interfaces on a 100Mbits network switch.
>
> Now that I added the SSDs, I'll test again. I'm currently looking on how to
> test.
> As I'm not interested in testing my OS cache, I'll reduce the memory to 1GB
> or less (with the mem=1024M kernel boot option), Install an ubuntu VM with
> 512MRam and PV disk drivers, and run either bonnie++ or iozone in these 4
> conditions :
> - Local SSD
> - DRBD SSD in Active-Active
> - Local SATA
> - DRBD Sata in Active-Active (but with the meta-disk on SSD). (Where I was
> getting 30IOPS with bonnie++ in my VM before I moved meta-disk to SSD)
>
> Regards,
>
> François Delpierre
>
> ________________________________
> De: "Eduardo Diaz - Gmail" <ediazrod at gmail.com>
> À: "François Delpierre" <francois.delpierre at pivert.org>
> Cc: drbd-user at lists.linbit.com
> Envoyé: Mardi 3 Janvier 2012 14:19:39
> Objet: Re: [DRBD-user] drbd performance issue on SATA
>
> I check the Network link too, because some times the network are the
> real problem.
>
> Did you test the network interface?.
>
> Did you change the the protocol to A for example.. and make more test.
>
> In my experience the SSD disk has problems for broken.
>
> http://www.codinghorror.com/blog/2011/05/the-hot-crazy-solid-state-drive-scale.html
>
> What configuration are you creating? Active/active, Active/passive?
> What filesystem?
>
> regards!
>
> On Sun, Jan 1, 2012 at 6:04 PM, François Delpierre
> <francois.delpierre at pivert.org> wrote:
>> Hi,
>>
>> I'm building a very low cost virtualization server for a Non Profit
>> organization using 2 HP workstations (500€ each) (8GB Ram, 1.5TB, QuadCore
>> AMD), Software Proxmox and DRBD for the data replication with dedicated
>> gigabit & cross cable for the replication.
>>
>> After setting up the replication (Protocol C), I had catastrophic
>> performances, ( dropping to 30 IOPS after 60s of random writes ).
>>
>> I also found a lot of reading, not fully explaining my terrific 30 IOPS on
>> 7200RPM drives, but clearly pointing the necessity to have a battery
>> backed
>> up cache controller to sustain random writes generated by the meta-disk.
>>
>> As the hardware makrket did change quite a lot recently, especially
>> towards
>> SSD, I immediately realized that 240GB SSD are half price than a small
>> raid
>> controller, a battery for the cache, and 2 small disks with reasonable
>> performances (10rpm). So, I choose SSD.
>>
>> I created 2 partitions on my SSD :
>> - 128MB for external meta-disk of my slow SATA partition (750GB)
>> - 240GB for a second DRBD resource, with internal meta-disk.
>>
>> My questions :
>> - Is there some recommendations on a SSD setup ?
>> - Why is the external meta-disk that few documented ? I spent more than 1
>> hour to find the syntax of the directive :
>>
>> meta-disk
>> /dev/disk/by-id/scsi-SATA_MKNSSDCR240GB_MKN1146A0000032XXX-part1[0];
>>
>> And it's not clear to my what is the [0] at the end ?
>>
>> Regards,
>>
>> François Delpierre
>>
>>
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>
>
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