and saw it *wouldn't* go beyond 8MB/s (sorry typo)<br><br>
<div class="gmail_quote">On Thu, Jun 19, 2008 at 9:28 PM, Marcelo Azevedo <<a href="mailto:marzevd@gmail.com">marzevd@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div>After placing the metadata on a different spindle (HD) , i was able to reach almost close to native speed (1-2MB/s less) </div>
<div> </div>
<div>with metadata internal i was reaching tops around half of the native speed , 37MB/s~ :</div>
<div> physical partition -> drbd -> ext3 </div>
<div> and </div>
<div>63MB/s~ with physical partition -> ext3 </div>
<div>61MB/s with metadata external, now this is true for another strong machine .</div>
<div> </div>
<div>This other machine has hardware RAID1 with two : </div>
<div>Cheetah T10 series,</div>
<div>146GB ,Serial Attached SCSI</div>
<div>Interface Speed: 3Gb/s </div>
<div>Spindle Rotation Speed: 15,000 RPM</div>
<div>Performance: 10K</div>
<div>on an IBM 2G Xeon server with 2 dual cpu packages , each cpu with 4 cores . <a href="http://publib.boulder.ibm.com/infocenter/eserver/v1r2/topic/diricinfo/fqy0_cibmraid.html" target="_blank"><font color="#551a8b"><b>IBM ServeRAID</b> SCSI controllers</font></a></div>
<div>
<div>4GB of ram</div></div>
<div>native speed -hardware raid1 -> physical partition -> ext3 is around 110MB/s ( still isn't this a bit slow for this HD ? )</div>
<div>hardware raid1 -> physical partition -> drbd -> ext3 - 101MB/s with </div>
<div>external metadata on a USB2 connected SATA HD 7,200 rpm</div>
<div> </div>
<div>now this is the crazy part - 8.3MB/s~ write speed ! with internal metadata , and 150MB/s read speed..</div>
<div>this test was repeated with bonnie , iozone and dd , all showed around same numbers , </div>
<div>i mean why the huge jump from 8MB/s to 100MB/s when using external metadata , and should this be STRESSED on the Docs or when starting the program that putting the metadata on external media improves performance significantly? , still i don't understand why i was able to reach only 8MB/s write speed on this strong server , maybe because of the hardware raid1 underneath?</div>
<div> </div>
<div> </div>
<div>kernel reports for the raid controller :</div>
<div>Adaptec aacraid driver 1.1-5[2437]-mh4<br>ACPI: PCI Interrupt 0000:04:00.0[A] -> GSI 17 (level, low) -> IRQ 16<br>PCI: Setting latency timer of device 0000:04:00.0 to 64<br>AAC0: kernel 5.2-0[15411] Oct 11 2007<br>
AAC0: monitor 5.2-0[15411]<br>AAC0: bios 5.2-0[15411]<br>AAC0: serial 402A183<br>AAC0: 64bit support enabled.<br>AAC0: 64 Bit DAC enabled<br>scsi0 : ServeRAID<br> Vendor: ServeRA Model: system Rev: V1.0<br> Type: Direct-Access ANSI SCSI revision: 02<br>
</div>
<div>drbd ver 8.2.6 (api:86/proto:86-88)</div>
<div> </div>
<div>at first i thought it was network performance issue , i benchmarked with ipref and reached 990Mbit gigabit speed, then i monitored the line with iptraf and saw 14MB/s tops writing speed on the drbd drive , and 50MB/s tops when doing synchronization</div>
<div> </div>
<div>so i tried on standalone mode , and saw it would go beyond 8MB/s with the benchmark tools , so it clearly wasn't a network issue</div>
<div> </div><font color="#888888">
<div>Marcelo.</div></font></blockquote></div><br>