I am not sure how valid this performance url is http://www.gluster.com/community/documentation/index.php/Guide_to_Optimizing_GlusterFS Does it make sense to separate out the journal and create mkfs -I 256? Also, if I already have a file system on a different partition can I still use it to store journal from other partition without corrupting the file system? On Thu, Apr 21, 2011 at 7:23 PM, Joe Landman <landman at scalableinformatics.com> wrote: > On 04/21/2011 08:49 PM, Mohit Anchlia wrote: >> >> After lot of digging today finaly figured out that it's not really >> using PERC controller but some Fusion MPT. Then it wasn't clear which > > PERC is a rebadged LSI based on the 1068E chip. > >> tool it supports. Finally I installed lsiutil and was able to change >> the cache size. >> >> [root at dsdb1 ~]# lspci|grep LSI >> 02:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E >> PCI-Express Fusion-MPT SAS (rev 08) > > ?This looks like PERC. ?These are roughly equivalent to the LSI 3081 series. > ?These are not fast units. ?There is a variant of this that does RAID6, its > usually available as a software update or plugin module (button?) to this. > ?I might be thinking of the 1078 chip though. > > ?Regardless, these are fairly old designs. > > >> [root at dsdb1 ~]# dd if=/dev/zero of=/data/big.file bs=128k count=40k >> oflag=direct >> 1024+0 records in >> 1024+0 records out >> 134217728 bytes (134 MB) copied, 0.742517 seconds, 181 MB/s >> >> I compared this with SW RAID mdadm that I created yesterday on one of >> the servers and I get around 300MB/s. I will test out first with what >> we have before destroying and testing with mdadm. > > So the software RAID is giving you 300 MB/s and the hardware 'RAID' is > giving you ~181 MB/s? ?Seems a pretty simple choice :) > > BTW: The 300MB/s could also be a limitation of the PCIe channel interconnect > (or worse, if they hung the chip off a PCIx bridge). ?The motherboard > vendors are generally loathe to put more than a few PCIe lanes for handling > SATA, Networking, etc. ?So typically you wind up with very low powered > 'RAID' and 'SATA/SAS' on the motherboard, connected by PCIe x2 or x4 at > most. ?A number of motherboards have NICs that are served by a single PCIe > x1 link. > >> Thanks for your help that led me to this path. Another question I had >> was when creating mdadm RAID does it make sense to use multipathing? > > Well, for a shared backend over a fabric, I'd say possibly. ?For an internal > connected set, I'd say no. ?Given what you are doing with Gluster, I'd say > that the additional expense/pain of setting up a multipath scenario probably > isn't worth it. > > Gluster lets you get many of these benefits at a higher level in the stack. > ?Which to a degree, and in some use cases, obviates the need for > multipathing at a lower level. ?I'd still suggest real RAID at the lower > level (RAID6, and sometimes RAID10 make the most sense) for the backing > store. > > > -- > Joseph Landman, Ph.D > Founder and CEO > Scalable Informatics, Inc. > email: landman at scalableinformatics.com > web ?: http://scalableinformatics.com > ? ? ? http://scalableinformatics.com/sicluster > phone: +1 734 786 8423 x121 > fax ?: +1 866 888 3112 > cell : +1 734 612 4615 >
