Hi All
Apologies if this topic has already been discussed.
We have a pair of V400 containing both FC and NL disks
We have performance issues with all the NL disks maxing out and a degree of DEL ACK's going on.
Due to an inbalance of services across our DC's, one of our FC tiers is at 84% - and the corresponding NL tier is pretty much full.
We would like to increase the performance of the system by putting in an SSD tier, but i'm not sure how to make best use of these with AO policies.
Our business is fairly dynamic, no two days are the same and we'd like our array to react to any hot data pretty quickly. Obviously there is a fairly hefty amount of financial outlay to introduce an SSD tier and as a storage team we need to make sure we are making the right recommendations!
Im sure some of you have had the same kind of issues to us and I'd welcome some advice/suggestions as to the best way to proceed - ideally ideas as to how to configure AO to react quickly to hot data.
Thanks
Dave
Leveraging SSD using AO
Re: Leveraging SSD using AO
Probably only 3.1.3(mu1) and its alleged flashcache feature can help you if todays hot isn't the same as yesterdays hot. This "might" take hot data and store to ssd and then trickle it to its normal tier - but as its not announced only some NDA's probably know how it might work and when it might appear.
Other than that, as a noob, the only thing that strikes me is to make your vv's be based out of the ssd tier so all writes go to ssd and then use AO to move the data down to FC and then to NL as it cools.
You can use DO to move/pin them to SSD but you obviously have to have enough room to store the volume of data coming in before AO can/decides to move it out - so probably 2 days of writes.
Other than that, as a noob, the only thing that strikes me is to make your vv's be based out of the ssd tier so all writes go to ssd and then use AO to move the data down to FC and then to NL as it cools.
You can use DO to move/pin them to SSD but you obviously have to have enough room to store the volume of data coming in before AO can/decides to move it out - so probably 2 days of writes.
Re: Leveraging SSD using AO
I do not think SSD will help you much as AO can take a while to get data where it needs to be and if that data patterns change then the long reaction time is not helping. We have seen similar issues. We are trying to get away from NL for anything other than snapshots due to the performance issues. We just bought a new 7400 and it is SSD and SAS 10K only.
Re: Leveraging SSD using AO
As mentioned, not sure if ssd with AO is going to help in this case as it'll be too slow to react by the sounds of it.
Do you need the performance of ssd for your app, would an extra couple of trays of sas not help, or maybe add some 15k sas disks?
The new flash cache mentioned above, I was told would be appearing in 3.1.4 which is probably 6 months off I'd say.
There is hp discover next week though where there will no doubt be a few announcements and I'm sure this will make an appearance.
Do you need the performance of ssd for your app, would an extra couple of trays of sas not help, or maybe add some 15k sas disks?
The new flash cache mentioned above, I was told would be appearing in 3.1.4 which is probably 6 months off I'd say.
There is hp discover next week though where there will no doubt be a few announcements and I'm sure this will make an appearance.