If you use LVM without striping, and Reiser FS on top of that, you don't even have to unmount the filesystems to resize them.
Striping takes away ALL of this advantage. We ran some tests with striped vs. non-striped filesystems, and generally got better results with striping, but I don't have numbers anymore. Regardless, I'm not sure if you would get much benefit out of striping the root FS, since the benefit of striping is in parallelizing I/O. The files in the root FS tend to be small, and are either read infrequently (at boot time), or read SO frequently that they tend to stay in the buffer cache. Write activity against the root FS should be EXTREMELY limited by design (although we had some products that stubbornly insist on putting things like dumps in /). > -----Original Message----- > From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of > Mrohs, Ray > Sent: Monday, January 24, 2005 9:41 AM > To: [email protected] > Subject: Re: [LINUX-390] Any caveats moving root filesystem to LVM? > > > Striping does give you more paths into storage, but I haven't seen any > performance studies of striped vs. non-striped LVM disks. If > you have fast > hardware and FICON, the advantage might not be that great. > With striping, you > lose the benefit of adding or removing physical volumes > dynamically in the volume > group (well, you still have to umount the file system > briefly), which means you > have to plan your file system growth really well, or take a > chunk of down time to > dump, resize, and reload whenever you need more space. We use > the non-striped > variety. > > Ray Mrohs > Energy Information Administration > U.S. Department of Energy > > > -----Original Message----- > From: David Andrews [mailto:[EMAIL PROTECTED] > Sent: Monday, January 24, 2005 8:50 AM > To: [email protected] > Subject: Re: Any caveats moving root filesystem to LVM? > > > On Fri, 2005-01-21 at 16:02 -0500, Mrohs, Ray wrote: > > My rule-of-thumb is to only use LVM when it's necessary, as > in providing more > > file system space than one minidisk can provide. > > There is also some striping value, no? (At least until Linux supports > PAV.) > > -- > David Andrews > A. Duda and Sons, Inc. > [EMAIL PROTECTED] > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [EMAIL PROTECTED] with the message: INFO > LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [EMAIL PROTECTED] with the message: INFO > LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > -------------------------------------------------------- If you are not an intended recipient of this e-mail, please notify the sender, delete it and do not read, act upon, print, disclose, copy, retain or redistribute it. Click here for important additional terms relating to this e-mail. http://www.ml.com/email_terms/ -------------------------------------------------------- ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
