Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
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 ----- Mail original ----- 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 > > > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20120104/071ae77a/attachment.htm>