What are some of the good controller cards would you recommend for SAS drives? Dell and Areca is what I am seeing most suggested online. On Tue, Apr 26, 2011 at 4:43 PM, Mohit Anchlia <mohitanchlia at gmail.com> wrote: > In your experience does it really help having journal on different > disk? Just trying to see if it's worth the effort. Also, Gluster also > recommends creating mkfs with larger blocks mkfs -I 256 > > As always thanks for the suggestion. > > On Tue, Apr 26, 2011 at 4:31 PM, Joe Landman > <landman at scalableinformatics.com> wrote: >> On 04/26/2011 05:48 PM, Mohit Anchlia wrote: >>> >>> 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? >> >> Journals are small write heavy. ?You really want a raw device for them. ?You >> do not want file system caching underneath them. >> >> Raw partition for an external journal is best. ?Also, understand that ext* >> suffers badly under intense parallel loads. ?Keep that in mind as you make >> your file system choice. >> >>> >>> 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 >>>> >> >> >> -- >> 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 >> >
