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VincePoore
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November 15th, 2014 21:00
Hot Spare Count and Proactive Copy
Article 7605 recommends 1 spare per 30 drive count. And the same recommendation can be found in VNX Applied Best Practices Guide.
But I am surprised there is no mention of the Proactive Copy feature. In a small array with only 2 DAEs (30 disks) and a single hot spare Proactive Copy would never be invoked. As a reminder, the proactive copy rules discussed in article 184475 require >1 available hot spares.
Proactive copy seems like a good feature to enable, but is there a reason this is not mentioned in the recommendations?
there is no difference - hot spare requirements are at least 1 hot spare per 30 disks on the same type. Proactive Hot sparing just means you need at least 1 hot spare not currently in use for this to work - as long as it is not for the same raid group or for a different type of disk.
glen
VincePoore
12 Posts
695
1
Posted November 18th, 2014 21:00
Well article 184475 says you need >1, i.e. at least 2 spares for proactive copy to initiate. That's what seemed at odds with the "all you need is 1" best practices recommendation.
Talking with support about 184475, the response was there are two scenarios for proactive copy. There is user initiated proactive copy and FLARE initiated proactive copy. User initiated requires 2 spares, FLARE initiated only 1.
I asked for the article to be revised to explain this distinction.
Raj10
37 Posts
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Posted November 22nd, 2014 11:00
Hi Vince,
If flare is initiating copy to hotspare function, 1 hotspare is fine. However, if user is manually invoking a hotspare for proactive copy, then you need to have at least 2 hotspares configured on array keeping 1 reserved for flare initiated proactive sparing.