First, let’s ground this in the context you shared:

新款服务器配备NVRAM-N DIMM，可在系统断电时将内存信息保存至闪存。据了解，信息保存耗时约1分钟，内置电池续航仅比RAM信息存入闪存所需时间多几秒，但暂未查询到从闪存恢复信息的耗时数据。

Now, let’s tackle your question about the maximum time to recover memory and restart the server:

What we can confirm (and what’s missing from public specs) #

• Save time is clear: As you noted, writing RAM contents to flash takes roughly 1 minute, with the onboard battery only adding a few extra seconds of buffer to ensure the save completes.
• Recovery time isn’t widely published: Most hardware vendors don’t list worst-case recovery times in public documentation, because it depends on a few key variables:
  • Total RAM capacity: More memory means more data to read back from flash—this is the biggest driver of recovery time.
  • Server platform optimizations: Some systems parallelize recovery across multiple DIMMs, while others process them sequentially, which slows things down.
  • Flash speed on the DIMM: Different NVRAM-N models use varying flash tech (like eMMC or embedded NVMe), which affects how fast data can be read back to RAM.

Realistic ballpark estimates for maximum recovery time #

While exact numbers depend on your setup, here’s a practical range to expect:

• For typical server configurations (1TB–2TB of DDR4 NVRAM-N), recovery time will likely be on par with the save time (1 minute) or slightly faster. Flash reads are usually quicker than writes, so you might see 30–60 seconds for recovery before the server proceeds to boot.
• For higher-capacity setups (4TB+), worst-case recovery could stretch to 90 seconds or more, especially if the server handles DIMMs sequentially.

How to get precise, vendor-specific numbers #

To get the exact maximum recovery time for your server and DIMM model:

1. Dig into the NVRAM-N DIMM’s technical datasheet—look for sections like “Power Failure Recovery” or “Restore Latency.”
2. Check your server’s BIOS/firmware docs—some systems let you tweak recovery settings, which can impact timing.
3. Reach out to the server or DIMM vendor’s support team—they’ll have internal testing data for worst-case scenarios that aren’t public.

内容的提问来源于stack exchange，提问作者Tmanok