----- Original Message ----- From: "John R Pierce" <pierce at hogranch.com> To: <centos at centos.org> Sent: Tuesday, July 12, 2011 8:34 AM Subject: Re: [CentOS] Suggest Hardware Raid Controller Card > On 07/11/11 5:16 PM, Christopher Chan wrote: >> Who needs bbu when you can get an SSD to work with your ext3/ext4 that is >> sitting on an md raid 1/0/nested 1+0/10? > > lI hope your SSD isn't write buffering on commits. many (most?) > consumer priced SSDs can corrupt file systems badly on power failures > during active file allocation operations, and drop pending database > writes on the floor. > > If an SSD doesn't do write buffering, its brutally slow relative to its > read speeds. Only the more expensive enterprise drives have 'supercap' > or other power backups for emergency buffer flushing in case of abrupt > power shutdowns. > Wait, wait. So using SSDs as FAST writing disks is a load of hogwash? You still need stuff like umem nvram cards? What's the deal with things like Fusion IO then?