Have a look at this.. http://www.spinics.net/lists/linux-btrfs/msg54779.html ---------- RAID5&6 devs_min values are in the context of degraded volume. RAID1&10.. devs_min values are in the context of healthy volume. RAID56 is correct. We already have devs_max to know the number of devices in a healthy volumes. RAID1's devs_min is wrong so it ended up being same as devs_max. ---------- Any comments? Also you may use the btrfs-raid-cal simulator tool to verify. https://github.com/asj/btrfs-raid-cal/blob/master/state-table Thanks, Anand On 08/15/2016 03:50 PM, Qu Wenruo wrote:
Hi, Recently I found that manpage of mkfs is saying minimal device number for RAID5 and RAID6 is 2 and 3. Personally speaking, although I understand that RAID5/6 only requires 1/2 devices for parity stripe, it is still quite strange behavior. Under most case, user use raid5/6 for striping AND parity. For 2 devices RAID5, it's just a more expensive RAID1. IMHO it's better to warn user about 2 devices RAID5 or 3 devices RAID6. Any comment is welcomed. Thanks, Qu -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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