2) Will I take a performance hit if I manually make two RAID1 sets and
then a RAID0 of them?

I'd rather use separate mirrors (raid1) and use lvm on top of that - better flexibility.

3) Should I forget about the layout and just use RAID6?

Depends what you need. RAID-6 will give you lower IOPS, but better sequencial I/O. It will also stand *any* two drives failing, while striped mirrors (raid-10 or raid-1 with raid-0/lvm on top) will only tolerate a single drive failing per mirror. The chances of two drives failing at the same time is low, but it's rather common to see a single drive failing and then seeing bad data on another drive. If not scterc (smartctl etc) is enabled, or the timeout (/sys/block/$dev/device/timeout) hasn't been increased, a single bad sector may make md kick out a drive, which would be bad if it's rebuilding a mirror. Personally, I use RAID-6 - it's safe and fast enough for my needs.

Vennlige hilsener / Best regards

roy
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Roy Sigurd Karlsbakk
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roy@karlsbakk.net
http://blogg.karlsbakk.net/
GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt
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I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med xenotyp etymologi. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk.
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