Forwarded as only I got the reply. ---------- Forwarded message ---------- From: Roberto Spadim <roberto@xxxxxxxxxxxxx> Date: Wed, Sep 18, 2013 at 7:41 AM Subject: Re: Best configuration for bcache/md cache or other cache using ssd To: Drew <drew.kay@xxxxxxxxx> Sorry guys, this time i don't have a full knowledge about the workload, but from what he told me, he want fast writes with hdd but i could check if small ssd devices could help After install linux with raid1 i will install apache mariadb and php at this machine, in other words it's a database and web server load, but i don't know what size of app and database will run yet Btw, ssd with bcache or dm cache could help hdd (this must be enterprise level) writes, right? Any idea what the best method to test what kernel drive could give superior performace? I'm thinking about install the bcache, and after make a backup and install dm cache and check what's better, any other idea? Em 18/09/2013 11:00, "Drew" <drew.kay@xxxxxxxxx> escreveu: > > HDD will be a SATA 7200rpm with 2TB, SSD will be ~ 160GB or less (must > > be cheap and enterprise level) > > > > he wants a RAID1 level over HDD and a cache (bcache/or md cache layer > > of kernel 3.9) over this md device (raid1) > > What is the client's workload? What is he trying to do with this machine? > > At first glance (without any information) the requirements don't make > sense. Placing a SSD based cache in front of a pair of slow 7200RPM > SATA's sounds like he's trying to get SSD performance at SATA prices. > It could work but if he's hammering the disks enough to need SSD > performance, those SATA's just won't keep up. > > > -- > Drew > > "Nothing in life is to be feared. It is only to be understood." > --Marie Curie > > "This started out as a hobby and spun horribly out of control." > -Unknown -- Drew "Nothing in life is to be feared. It is only to be understood." --Marie Curie "This started out as a hobby and spun horribly out of control." -Unknown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
