Data loss could conceivably occur on shutdown or restart too - just saying... You are assuming that the data that doesn't get written to disk is going to be non-essential... I wish you good luck with that. I think if one doesn't want to be an idiot, one would not enable a cache that has no means to ensure that the cache is written to disk. I think your take away from all of this is somewhat misdirected. Not having a BBU simply means that your writes really should always be synchronous/immediate. That shouldn't really be a problem and shouldn't impose a large performance penalty. Your performance issue relates more to the fact that RAID 5 implementation on the 3Ware cards is rather poor and modes such as RAID 10 (RAID 0 + 1) will give you much more speed that you realize. If you also consider on the surprisingly higher rates of failure with loss of data possibility when reconstructing a missing/dead drive on a RAID 5 setup you really should be re-examining your storage strategy. Craig On Sep 1, 2011, at 5:43 PM, Austin Godber wrote: > At this point the card is pretty much useless without that cache enabled. Without recommendations for making writes of 256MB or larger files faster without this cache enabled, I will have to accept the possible data loss in the event of power outage. If it is only the case of data loss during a power outage, I will take that ... rather than failure to write at all during 99% of my usage. > > I will, for the sake of not being an idiot, look into buying the BBUs. > > Austin > > On Thu, Sep 1, 2011 at 4:49 PM, Tom Bishop <bishoptf at gmail.com> wrote: > Keep in mind you really only want to enable the cache if you have a > bbc, otherwise you are risking your data since it can/will cache > writes...just something to keep in mind. > > On 9/1/11, Austin Godber <godber at gmail.com> wrote: > > Hi Craig, > > > > Thanks for the suggestion. I would if I could. I'd also probably try > > another file system. Though the good news is, enabling the write cache on > > that array has improved things significantly. Which, in my case, was: > > > > tw_cli /c2/u0 set cache=on > > > > Now, if only I had the battery backup unit for the card. > > > > Thanks, everyone for their suggestions. For now I am happy with the > > situation, but I'd be interested to hear the experiences of others. > > > > Austin > > > > On Thu, Sep 1, 2011 at 3:58 PM, Craig White <craig.white at ttiltd.com> wrote: > > > >> > >> On Sep 1, 2011, at 1:41 PM, Austin Godber wrote: > >> > >> > Hello, > >> > > >> > Does anyone have experience using a 3ware 9650SE series raid controller > >> on CentOS 6.0? > >> ---- > >> use RAID 10 > >> > >> Unless something has changed, RAID 5 is notoriously slow on the 3Ware > >> controllers. Whatever you do will only incrementally speed things up. If > >> performance is desired, RAID 5 is not the way to go. > >> > >> Craig > >> _______________________________________________ > >> CentOS mailing list > >> CentOS at centos.org > >> http://lists.centos.org/mailman/listinfo/centos > >> > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos -- Craig White ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ craig.white at ttiltd.com 1.800.869.6908 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ www.ttiassessments.com Need help communicating between generations at work to achieve your desired success? Let us help!