Well for those people who don't have 4TB SSDs, wonder if anyone has gone the cache route?
Well, what I'd like to do - I have a 4TB disk array (RAID5) and would like to add an SSD cache to speed up operations.
Don't worry about the implementation - though I am using Linux LVM and planning on using LVM's built-in disk cache functionality, but again don't worry about it. Assume that I can suddenly add an SSD cache.
What I wonder is how much of an improvement I'll see in multiple I/O consumers. The disk array is currently being accessed by multiple IO streams and is getting killed by this fact, as expected. I wonder how much of a SSD would cause an improvement in interactive performance or will it be mandatory that I have an SSD of the same size of my array to get any benefit? I'm worried about write performance as well, unfortunately this will be bottlenecked by the underlying HDD, perhaps I am forced to use writeback caching to improve performance?
I'm hoping I can get away with a much smaller SSD than the 4T on the array. Also wonder how badly will the SSD get trashed in terms of write cycles/lifetime?
Anyone using such a setup?
Well, what I'd like to do - I have a 4TB disk array (RAID5) and would like to add an SSD cache to speed up operations.
Don't worry about the implementation - though I am using Linux LVM and planning on using LVM's built-in disk cache functionality, but again don't worry about it. Assume that I can suddenly add an SSD cache.
What I wonder is how much of an improvement I'll see in multiple I/O consumers. The disk array is currently being accessed by multiple IO streams and is getting killed by this fact, as expected. I wonder how much of a SSD would cause an improvement in interactive performance or will it be mandatory that I have an SSD of the same size of my array to get any benefit? I'm worried about write performance as well, unfortunately this will be bottlenecked by the underlying HDD, perhaps I am forced to use writeback caching to improve performance?
I'm hoping I can get away with a much smaller SSD than the 4T on the array. Also wonder how badly will the SSD get trashed in terms of write cycles/lifetime?
Anyone using such a setup?
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