| Subject | RE: [firebird-support] Re: FB database in RAM - Email found in subject |
|---|---|
| Author | Leyne, Sean |
| Post date | 2011-08-05T14:27:47Z |
I wrote:
When using RAID5 disk controllers will write large blocks/stripes to disk, so a single 4KB page update can result in the controller actually writing 64KB* to the SSD. This a form of "write amplification" and will increase the speed of SSD failure.
Sean
* The block size can be even larger, up to 1MB, so the selection of stripe size is very important. For example, Adaptec has a default strip size of 256KB.
> We have purchasedI forgot one other issue...
> many SSD (even a Fusion IO PCI-E SSD solution) and here are a couple of
> things to be aware of:
When using RAID5 disk controllers will write large blocks/stripes to disk, so a single 4KB page update can result in the controller actually writing 64KB* to the SSD. This a form of "write amplification" and will increase the speed of SSD failure.
Sean
* The block size can be even larger, up to 1MB, so the selection of stripe size is very important. For example, Adaptec has a default strip size of 256KB.