----- Original Message ----- From: "John R Pierce" pierce@hogranch.com To: centos@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?