From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.grid-net.com ([97.65.115.2]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SLMng-00060C-Rn for linux-mtd@lists.infradead.org; Fri, 20 Apr 2012 22:59:37 +0000 Message-ID: <4F91EA56.50803@grid-net.com> Date: Fri, 20 Apr 2012 15:59:34 -0700 From: Subodh Nijsure MIME-Version: 1.0 To: mtd Subject: Suggestion needed to set proper journal size Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello, I know general implications of changing journal size on UBIFS -- bigger the journal, longer it may take to replay the journal, increasing time UBIFS takes to mount. Smaller journal means more re-writes to flash. We created 2 partitions 100MB and 45MB and we see that by default mkfs.ubifs is reserving 8MB for journal. UBIFS: file system size: 101834752 bytes (99448 KiB, 97 MiB, 802 LEBs) UBIFS: journal size: 9023488 bytes (8812 KiB, 8 MiB, 72 LEBs) UBIFS: file system size: 47996928 bytes (46872 KiB, 45 MiB, 378 LEBs) UBIFS: journal size: 9023488 bytes (8812 KiB, 8 MiB, 72 LEBs) I know I can specify size of journal with -j option. Should the journal size be scaled in some proportion of size of UBIFS partition? Should the journal size depend on how often you expect file-system to be updated? Has anyone done experiments with setting really small (1MB/2MB) journal size? What side effects is one likely to encounter if the journal size is too small. fwiw in my use case, file-system doesn't get updated that often, perhaps 2K data in about 4 files once a week. -Subodh