Bitmaps & Kernel Versions
Hi,
I'm planning to use bitmaps on some of our RAID1 arrays.
I'm wondering how bitmaps are handeled by older kernels.
Eg: I create a raid array with a bitmap under a 2.6.15 kernel.
I now want to boot under 2.6.12, or even 2.4
Hos is it handeled?
Will it work even if this is my / partition?
Thanks
Laurent
Quoted 6 lines · On Wednesday March 15, [email protected] wrote:
Hi,
I'm planning to use bitmaps on some of our RAID1 arrays.
I'm wondering how bitmaps are handeled by older kernels.
Quoted 7 lines
Eg: I create a raid array with a bitmap under a 2.6.15 kernel.
I now want to boot under 2.6.12, or even 2.4
Hos is it handeled?
Will it work even if this is my / partition?
On older kernel will not notice the bitmap and will behave 'normally'.
When you go back to a kernel that understands bitmaps, it will notice that the bitmap is now out-of-date and will not trust it, but should start putting fresh data into it.
So it *should* all "just work". However it hasn't been extensively tested so I'm not giving any guarantees.
NeilBrown
Quoted 9 lines · Neil Brown
Quoted 8 lines · On Wednesday March 15, [email protected] wrote:
Hi,
I'm planning to use bitmaps on some of our RAID1 arrays.
I'm wondering how bitmaps are handeled by older kernels.
Eg: I create a raid array with a bitmap under a 2.6.15 kernel.
Quoted 9 lines
Quoted 5 lines
I now want to boot under 2.6.12, or even 2.4
Hos is it handeled?
Will it work even if this is my / partition?On older kernel will not notice the bitmap and will behave 'normally'.
strange,
last time i tried an older kernel would refuse to activate an md with a bitmap on it.
I am far from home on a business trip and i don't have kernel-sources at hand, but i seem to remember that the kernel was very strict on the feature bitmap in the superblock.
L.
Signature · 6 lines
Luca Berra -- [email protected] Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \
Quoted 22 lines · Luca Berra
Quoted 13 lines · Neil Brown
Quoted 11 lines · On Wednesday March 15, [email protected] wrote:
Hi,
I'm planning to use bitmaps on some of our RAID1 arrays.
I'm wondering how bitmaps are handeled by older kernels.
Eg: I create a raid array with a bitmap under a 2.6.15 kernel.
I now want to boot under 2.6.12, or even 2.4
Quoted 6 lines
Quoted 2 lines
Hos is it handeled?
Will it work even if this is my / partition?On older kernel will not notice the bitmap and will behave 'normally'.
Quoted 9 lines
strange,
last time i tried an older kernel would refuse to activate an md with a bitmap on it.
I am far from home on a business trip and i don't have kernel-sources at hand, but i seem to remember that the kernel was very strict on the feature bitmap in the superblock.L.
I experienced the same strange behavior.
Bitmap was created on 2.6.15, tried to boot 2.6.14 and /dev/md0 was not started :$.
Strange.....
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